The global energy demand is increasing at the same time as fossil fuel resources are dwindling. Consequently, the search for alternative energy sources is a major topic worldwide. Solar energy is one of the most promising, effective and emission-free energy sources. However, the energy has to be stored to compensate the fluctuating availability of the sun and the actual energy demand. Photo-rechargeable electric energy storage systems may solve this problem by immediately storing the generated electricity. Different combinations of solar cells and storage devices are possible. High efficiencies can be achieved by the combination of dye-sensitized solar cells (DSSC) and capacitors. However, other hybrid devices including DSSCs or organic photovoltaic systems and redox flow batteries, lithium ion batteries and metal air batteries are playing an increasing role in this research field. This Progress Report reviews the state of the art research of photo-rechargeable batteries based on organic solar cells, as well as storage modules.

The incorporation of reversible covalent bonds into polymeric materials offers the possibility to generate polymers with self-healing ability. For this purpose, three new oxime crosslinkers are synthesized and crosslinked by the copolymerization with different commercially available methacrylates via a photo-polymerization process. These crosslinked materials are investigated regarding a potential self-healing behavior. Moreover, the influence of different additives (polymerizable acids, photo acids, and acid developers) to enable self-healing is studied in detail. Thereby, the limit of self-healing based on reversible covalent bonds is reached in these materials. Due to the high stability of the oxime bonds in bulk materials no exchange reactions as well as no self-healing behavior could be observed. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44168.

Poly(butyl methacrylate) copolymers embedding bidentate 2-(1,2,3-triazol-4-yl)pyridine (trzpy) chelating units as comonomer in the side chains were synthesized by controlled radical addition-fragmentation transfer (RAFT) polymerization. Intracomplexation and intercomplexation of the macromolecules of the poly(butyl methacrylate) copolymers containing 20 % mol of trzpy units induced by Co^II, Fe^II, and Eu^III ions were studied in the solutions by macromolecular hydrodynamics methods. The sedimentation velocity of extremely diluted copolymer solutions and the dynamic viscosity of moderately diluted solutions were studied in a wide range of the salts concentrations. Differences were observed with respect to the copolymer behavior in the presence of the Co²⁺, Fe²⁺, Eu³⁺ ions. These differences are namely due to the differences in the number of coordination bonds required for complex formation and not explicitly to the nature of the corresponding anions. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 2632–2639

The synthesis of novel polymeric dyes by directly attaching toluidine blue O and MPPD via EDC and CDI coupling is described for polymers with enteric properties [poly(methacrylic acid-co-ethyl acrylate)]. The polymeric dyes are analyzed by SEC and UV/Vis measurements as well as investigated regarding their dissolution and permeation characteristics. Almost no changes between the modified and nonmodified polymer could be observed by conventional drug studies and a self-established method for dissolution rates. Also no influence on the film formation properties was observed by SEM measurements. In vitro toxicity studies showed no increase of toxicity compared to the non modified polymer. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 2386–2393

Redox-active anthraquinone based polymers are synthesized by the introduction of a polymerizable vinyl and ethynyl group, respectively, resulting in redox-active monomers, which electrochemical behaviors are tailored by the modification of the keto groups to N-cyanoimine moieties. These monomers can be polymerized by free radical polymerization and Rh-catalyzed polymerization methods, respectively. The resulting polymers are obtained in molar masses (M_n) of 4,400 to 16,800 g mol⁻¹ as well as high yields of up to 97%. The monomers and polymers are furthermore electrochemically characterized by cyclic voltammetry. The monomers exhibit two one-electron redox reactions at about −0.6 and −1.0 V versus Fc⁺/Fc. The N-cyanoimine units are, however, partially hydrolyzed during the polymerization step or during the electrochemical measurements and degenerate to carbonyl groups, resulting in a new reduction signal at −1.26 V versus Fc⁺/Fc. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 1998–2003

A simple and convenient method for the synthesis of end functionalized polylactides (PLAs) under mild conditions by ring opening polymerization (ROP) in the absence of potentially toxic catalysts is described. Various alcohols were used as initiators in combination with Ca[N(SiMe₃)₂]₂(THF)₂ as the precatalyst in THF at room temperature. Tailored end functionalities were obtained in a controlled fashion. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToF-MS) and electrospray ionization quadrupole time of flight mass spectrometry (ESI-Q-ToF-MS) analysis were performed to investigate the end groups. The results confirmed that the end group fidelity was maintained in the isolated PLAs. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 437–448

Redox-active polymers enhanced the focus of attention in the field of battery research in recent years. Anthraquinone is one of the most generic redox-active functional compounds for battery applications, because the quinonide structure undergoes a redox reaction involving two electrons and features stable electrochemical behavior. Although various redox-active polymers have been developed, the polymer backbone is mostly based on linear alkyl chains [e.g., poly(methacrylate)s, poly(ether)s]. Polymers featuring ring structures in the backbone are limited due to the restricted availability of suitable polymerization techniques [e.g., poly(norbornene)s by ROMP]. The cyclopolymerization of dienes with pendant redox-active anthraquinone moieties by Pd catalysis represents a novel approach to synthesize redox-active polymers featuring cyclic structures in the backbone. Electrochemical investigations, in particular cyclic voltammetry, of these new diene monomer, polymers and the corresponding polymer supported carbon paper composites were conducted in different organic electrolytes. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 2184–2190

The application of organic carbonyl compounds as high performance electrode materials in secondary batteries enables access to metal-free, low-cost, environmental friendly, flexible, and functional rechargeable energy storage systems. Organic compounds have so far not received much attention as potential active materials in batteries, mainly because of the success of inorganic materials in both research and commercial applications. However, new requirements in secondary batteries such as flexibility accompanied with low production costs and environmental friendliness, in particular for portable devices, reach the limit of inorganic electrode materials. Organic carbonyl compounds represent the most promising materials to satisfy these needs. Here, recent efforts of the research in the field of organic carbonyl materials for secondary batteries are summarized, and the working principle and the structural design of different groups of carbonyl material is presented. Finally, the influence of conductive additives and binders on the cell performance is closely evaluated for each class of materials.

The utilization of dynamic covalent and noncovalent bonds in polymeric materials offers the possibility to regenerate mechanical damage, inflicted on the material, and is therefore of great interest in the field of self-healing materials. For the design of a new class of self-healing materials, methacrylate containing copolymers with acylhydrazones as reversible covalent crosslinkers are utilized. The self-healing polymer networks are obtained by a bulk polymerization of an acylhydrazone crosslinker and commercially available methacrylates as comonomers to fine-tune the T_g of the systems. The influence of the amount of acylhydrazone crosslinker and the self-healing behavior of the polymers is studied in detail. Furthermore, the basic healing mechanism and the corresponding mechanical properties are analyzed.

Fast and easy purification and amplification of DNA are prerequisites for the development of point-of-care diagnostics. For this reason covalent coatings of amine containing poly(2-oxazoline)s (POx) on glass and poly(propylene) surfaces are prepared, to reversibly bind genetic material directly from biological samples. The polymer is deposited in a layer-by-layer process, whereas initial immobilization of macromolecules on the surface is accomplished by the use of an epoxy functionalized siloxane monolayer. Alternating treatment with polymer and cross-linker leads to the construction of amine containing POx multilayers on the substrates. Successful deposition is investigated by confocal laser scanning microscopy (using labeled polymers), contact angle measurements, as well as reflectometric interference spectroscopy. The interaction of these layer systems with DNA regarding binding and temperature dependent release is studied using labeled genetic material. Finally, polymerase chain reaction (PCR) vessels are coated with POx layers on the inside, and used for quantitative real-time PCR (qPCR) experiments. It is possible to bind genetic material directly from cell lysates to perform qPCR assays from surface adsorbed DNA within the same tube including amplification, as well as detection. The presented system displays an easy to use device for a point of care diagnostic.

Diblock copolymers of poly[2-(dimethylamino)ethyl methacrylate]-block-poly[di(ethylene glycol) methyl ether methacrylate], PDMAEMA-b-PDEGMA, were synthesized by reversible addition–fragmentation chain transfer polymerization. The block ratio was varied to study the influence on the lower critical solution temperature and the corresponding phase transition in water. Therefore, turbidimetry, differential scanning calorimetry (DSC), dynamic light scattering (DLS), and laser Doppler velocimetry were applied. Additionally, asymmetric flow field-flow fractionation (AF4) coupled to DLS and multiangle laser light scattering (MALLS) was established as an alternative route to characterize these systems in terms of molar mass of the polymer chain and size of the colloids after the phase transition. It was found that AF4–MALLS allowed accurate determination of molar masses in the studied range. Nevertheless, some limitations were observed, which were critically discussed. The cloud point and phase transition of all materials, as revealed by turbidimetry, could be confirmed by DSC. For block copolymers with block ratios in the range of 50:50, a thermo-induced self-assembly into micellar and vesicular structures with hydrodynamic radii (R_h) of around 25 nm was observed upon heating. At higher temperatures, a reordering of the self-assembled structures could be detected. The thermo-responsive behavior was further investigated in dependence of pH value and ionic strength. Variation of the pH value mainly influences the solubility of the PDMAEMA segment, where a decrease of the pH value increases the transition temperature. An increase of ionic strength leads to a reduction of the cloud point due to the screening of electrostatic interactions. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 924–935

Redox-active polymers draw significant attention as active material in secondary batteries during the last decade. A new anthraquinone-based redox-active monomer was designed, which electrochemical behavior was tailored by mono-modification of one keto group. The monomer exhibits two one-electron redox reactions and has a low molar mass, resulting in a high theoretical capacity of 207 mAh/g. The polymerization of the monomer was optimized by variation of solvent and initiator. Moreover, the electrochemical behavior was studied using cyclic voltammetry and the polymer was used as active material in a composite electrode in lithium organic batteries. The polymer reveals a cell potential of 2.3 V and a promising capacity of 137 mAh/g. During the first 100 cycles, the capacity drops to 85% of the initial value. The influence of the charging speed on the charging/discharging properties of the batteries was further investigated. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 2517–2523

A series of poly(ethylene glycol)-block-poly(allyl glycidyl ether) (PEG-b-PAGE) macroinitiators are prepared using the living anionic ring-opening polymerization (AROP) technique, and applied for further copolymerization studies. To overcome the low reactivity of the secondary hydroxyl end-group of the PAGE block, a primary hydroxyl group is introduced into the macroinitiators via trityl and tert-butyl-dimethylsilane protective groups. The modified macroinitiators are used for copolymerization by applying different amounts of PEG-b-PAGE (5, 10, and 15%) and different PLGA lengths. To study their properties, nanoparticles from selected polymers are prepared and characterized by dynamic light scattering and scanning electron microscopy showing spherical particles with diameters around 200 nm and low PDI_particle values of 0.03–0.1. An advantage of the obtained polymers is the presence of double bonds in the side chain, which enables the modification via, for example, thiol-ene reactions. For this purpose tertiary 2-(dimethylamino)ethanethiol), acetylated thiogalactose and thiomannose are attached onto the double bonds of the PAGE-blocks. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 2163–2174

In this study, we designed and investigated pH-responsive nanoparticles based on different ratios of monomers with primary, secondary or tertiary amino groups. For this purpose, copolymers of methyl methacrylate (MMA) with different compositions of amino methacrylates (2-(dimethylamino)ethyl methacrylate (DMAEMA), 2-(tert-butylamino)ethyl methacrylate (tBAEMA) and 2-aminoethyl methacrylate hydrochloride (AEMA·HCI)) were synthesized using the reversible addition-fragmentation chain transfer (RAFT) polymerization process. The controlled nature of the radical polymerization was demonstrated by kinetic studies. All copolymers show low dispersities (Đ_M < 1.2) with amino contents between 9 and 21 mol %. For the nanoparticle formation, nanoprecipitation with subsequent solvent evaporation was used. All suspensions were characterized by dynamic light scattering (DLS) and scanning electron microscopy (SEM). Different initial conditions of the formulations resulted in differently sized nanoparticles that have monomodal size distributions, relatively narrow polydispersity index (PDI) values and positive zeta potential values. The pH-stability test results demonstrated that, depending on the structure and amount of the amino content, the obtained nanoparticles reveal a reversible pH-response, such as dissolution at acidic pH values. The ability of the nanoparticles to encapsulate guest molecules was confirmed by pyrene fluorescence studies. The cytotoxicity assay results showed that the nanoparticles did not have any significant cytotoxic effect. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 2711–2721

“Click” chemistry is an effective and commonly used technique in polymer chemistry for the synthesis and modification of polymers. In this study, the bulk polymerization of multifunctional alkynes and azides was achieved by the copper(I)-catalyzed alkyne–azide 1,3-dipolar cycloaddition. The influence of different catalyst systems on the polymerization kinetics of the “click”reaction were evaluated by differential scanning calorimetry. Surprisingly, Cu(I) acetate showed the most efficient catalytic behavior among the applied Cu(I) salts. The polymerization kinetics in solution were investigated by 1H NMR spectroscopy and size exclusion chromatography. According to the 1H NMR investigation the copper(I)-catalyzed cycloaddition follows a second-order kinetics with external catalysis. Additionally, the mechanical properties of the resulting polymers were investigated by depth sensing indentation. Thereby the polymerizations of the alkyne tripropargylamine with the azides 1,3-bis(azidomethyl)benzene and 1,4-bis(azidomethyl)benzene resulted in mechanical hard materials. Furthermore, the combination of the alkynes tripropargylamine and di(prop-2-yn-1-yl) isophorone dicarbamate and polymerization with 1,2-bis(2-azidoethoxy)ethane resulted in high indentation moduli. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 239–247

The anodic electropolymerization of thiophene-functionalized cyclometalated ruthenium(II) complexes is shown for the first time. Oxidative decomposition reactions can be overcome by modification of the involved redox potentials through the introduction of electron-withdrawing substituents, namely nitro groups, at the cyclometalating phenyl ring. The generated functionalized ruthenium(II) complexes allow the electrochemical preparation of thin polymer films, which show a broad UV/Vis absorption as well as reversible redox switchability. The presented complexes are promising candidates for future photovoltaic applications based on photo-redox-active films.

The application of well-defined poly(furfuryl glycidyl ether) (PFGE) homopolymers and poly(ethylene oxide)-b-poly(furfuryl glycidyl ether) (PEO-b-PFGE) block copolymers synthesized by living anionic polymerization as self-healing materials is demonstrated. This is achieved by thermo-reversible network formation via (retro) Diels-Alder chemistry between the furan groups in the side-chain of the PFGE segments and a bifunctional maleimide crosslinker within drop-cast polymer films. The process is studied in detail by differential scanning calorimetry (DSC), depth-sensing indentation, and profilometry. It is shown that such materials are capable of healing complex scratch patterns, also multiple times. Furthermore, microphase separation within PEO-b-PFGE block copolymer films is indicated by small angle X-ray scattering (lamellar morphology with a domain spacing of approximately 19 nm), differential scanning calorimetry, and contact angle measurements.

Two rodlike ruthenium(II) complexes of 2,6-di(quinolin-8-yl)pyridines (dqp) were synthesized and possess a pair of 2-thienyl moieties attached to the 4-positions of the quinoline units of one ligand or at the 4-positions of the pyridine rings of both ligands. The heteroleptic and homoleptic complexes were characterized by UV/Vis absorption and emission spectroscopy as well as electrochemical and X-ray crystallographic means. The subsequent electropolymerization of the thiophene units led to the controlled formation of thin solid films onto electrode surfaces as proven by X-ray photoelectron spectroscopy (XPS). The electrochemical analysis of the films was complemented by UV/Vis spectroscopy and UV/Vis/NIR spectroelectrochemistry, which revealed their stability towards oxidation, red emission, and reversible redox switching of their optical properties. Density functional theory (DFT) calculations were executed on the monomer complexes and respective dimeric systems to gain insight into their spectroscopic and electrochemical properties.

The thin-film properties of a polymer library consisting of novel conjugated low-bandgap poly(diketopyrrolopyrrole-co-benzothiadiazole-co-fluorene) (poly(DPP-co-BTD-co-F)) polymers are investigated. The content of the monomer units in the copolymers is systematically varied. Structure–property relationships are obtained for the ink characteristics, the film formation qualities, and their optical properties. Toluene/o-DCB in a ratio 90/10 and a concentration of 5 mg mL⁻¹ is found to be a suitable solvent system for all polymers. The polymer compositions and the choice of solvent have a significant influence on the film properties. Inkjet printing is shown to be a suitable technique for the preparation of thin-film libraries that subsequently can be characterized by combinatorial screening tools.

A systematic investigation of the relationships between the choice of solvent system and the film quality of inkjet printed π-conjugated polymer films is presented. Solution properties, such as surface tension and viscosity, have no effect on the final film quality, whereas the boiling point of the solvent and, more specifically, the difference in boiling point between the main and the co-solvent have a strong influence on the final film quality. New solvent systems are developed based on non-chlorinated, aromatic solvents that reveal homogeneous films when the difference in boiling point between the main and the co-solvent is between 90 and 100 °C.

A series of heteroleptic bis(tridentate) Ru^II complexes featuring N^C^N-cyclometalating ligands is presented. The 1,2,3-triazole-containing tridentate ligands are readily functionalized with hydrophobic side chains by means of click chemistry and the corresponding cyclometalated Ru^II complexes are easily synthesized. The performance of these thiocyanate-free complexes in a dye-sensitized solar cell was tested and a power conversion efficiency (PCE) of up to 4.0 % (J_sc=8.1 mA cm⁻², V_oc=0.66 V, FF=0.70) was achieved, while the black dye ((NBu₄)₃[Ru(Htctpy)(NCS)₃]; Htctpy=2,2′:6′,2′′-terpyridine-4′-carboxylic acid-4,4′′-dicarboxylate) showed 5.2 % (J_sc=10.7 mA cm⁻², V_oc=0.69 V, FF=0.69) under comparable conditions. When co-adsorbed with chenodeoxycholic acid, the PCE of the best cyclometalated dye could be improved to 4.5 % (J_sc=9.4 mA cm⁻², V_oc=0.65 V, FF=0.70). The PCEs correlate well with the light-harvesting capabilities of the dyes, while a comparable incident photon-to-current efficiency was achieved with the cyclometalated dye and the black dye. Regeneration appeared to be efficient in the parent dye, despite the high energy of the highest occupied molecular orbital. The device performance was investigated in more detail by electrochemical impedance spectroscopy. Ultimately, a promising Ru^II sensitizer platform is presented that features a highly functionalizable “click”-derived cyclometalating ligand.

Within this study, we report on the first controlled radical polymerization of styrene-based models of the active site of the [FeFe]-hydrogenase. Three different model complexes based on styrene were prepared including propanedithiolato-bridged, 2-azapropanedithiolato-bridged, and bifunctional styrene iron complex. These model complexes were copolymerized with styrene using free radical and the reversible addition-fragmentation chain transfer polymerization method. The polymerization behavior of the hydrogenase models is discussed and analyzed in detail. It could be shown that the model complex can be incorporated into copolymers. The obtained copolymers exhibit narrow molar mass distributions. The presence of the [FeFe]-hydrogenase models were proven by atomic absorption spectrometry, NMR and IR spectroscopy as well as cyclovoltammetric measurements. It could be shown that the [FeFe]-hydrogenase mimic copolymers, as well as the monomeric originating complexes exhibit electrocatalytic proton reduction at a low potential of –2.2 V. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013

The Förster resonance energy transfer (FRET) properties in poly(methyl methacrylate) copolymers containing 2-(pyridine-2-yl) thiazole dyes were studied upon systematic variation of the donor-to-acceptor ratio. To this end, 2-(pyridine-2-yl) thiazole dyes specially designed for the usage as energy donor and acceptor molecules were incorporated within one polymer chain. Poly(methyl methacrylate) copolymers containing these donor and acceptor dyes were synthesized using the RAFT polymerization method. Copolymers with a molar mass (M_n) of nearly 10,000 g/mol were achieved with dispersity index values (Đ) under 1.3. The presented copolymers act as a model system for the FRET investigation. Förster resonance energy transfer properties of the copolymers are characterized by steady state as well as time resolved fluorescence spectroscopy. The results indicate that the energy transfer rates and the transfer efficiencies are tunable by variation of the donor-acceptor-ratio. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4765–4773

A new modular approach based on Pd-catalyzed CC bond formation is presented for the assembly of a benzannulated azocine scaffold, the key intermediate in the synthesis of functionalized azadibenzocyclooctynes (aza-DIBOs). The intramolecular ring-closing Heck coupling was investigated by variation of the CX bond. The reaction rate is limited by the initial oxidative addition step and the regiochemistry strongly depends on the auxiliary phosphine. Under optimized conditions, the 8-endo regioisomer was obtained in 71 % yield over two steps (with no protecting group chemistry) or in one pot, inclusive of CN bond formation. The practical generation of the octyne triple bond of a prototypical N-benzoyl aza-DIBO, without the need for chromatographic purification, is also described. The structural features, including those of the ring-strained cyclic octyne, were elucidated by NMR spectroscopy and X-ray crystallographic analysis. The high reactivity of the N-benzoyl aza-DIBO synthesized is demonstrated in a strain-promoted azide–alkyne cycloaddition reaction with an alkyl azide (k=0.38 M⁻¹ s⁻¹).

A series of comb polymers consisting of a methacrylate backbone and poly(2-ethyl-2-oxazoline) (PEtOx) side chains was synthesized by a combination of cationic ring-opening polymerization and reversible addition–fragmentation chain transfer polymerization. Small-angle neutron scattering (SANS) studies revealed a transition from an ellipsoidal to a cylindrical conformation in D₂O around a backbone degree of polymerization of 30. Comb-shaped PEtOx has lowered T_g values but a similar elution behavior in liquid chromatography under critical conditions in comparison to its linear analog was observed. The lower critical solution temperature behavior of the polymers was investigated by turbidimetry, dynamic light scattering, transmission electron microscopy, and SANS revealing decreasing T_cp in aqueous solution with increasing molar mass, the presence of very few aggregated structures below T_cp, a contraction of the macromolecules at temperatures 5 °C above T_cp but no severe conformational change of the cylindrical structure. In addition, the phase diagram including cloud point and coexistence curve was developed showing an LCST of 75 °C of the binary mixture poly[oligo(2-ethyl-2-oxazoline)methacrylate]/water. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013

A homotelechelic macroligand bearing two 2,2′:6′,2″-terpyridin-4′-yl units, as chain ends, is used as building block for the preparation of a linear metallo-supramolecular chain-extended polymer. The macroligand has been prepared by nitroxide-mediated polymerization (NMP) of styrene using a bis-terpyridine-functionalized NMP initiator. The controlled character of the NMP process has been confirmed by detailed characterization of the polymer by size-exclusion chromatography, nuclear magnetic resonance spectroscopy as well as mass spectrometry. Subsequently, the self-assembly with Fe^II ions into the chain-extended metallopolymer and the disassembly thereof, in the presence of a strong competitive ligand, has been studied by UV–vis absorption spectroscopy and diffusion-ordered NMR spectroscopy. The reversibility of the formation of the metallo-supramolecular material, when addressed by external stimuli, could be proven. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013

Electropolymerization represents a suitable and well-established approach for the assembly of polymer structures, in particular with regard to the formation of thin, insoluble films. Utilization of monomers that are functionalized with metal complex units allows the combination of structural and functional benefits of polymers and metal moieties. Since a broad range of both electropolymerizable monomers and metal complexes are available, various structures and, thus, applications are possible. Recent developments in the field of synthesis and potential applications of metal-functionalized polymers obtained via electropolymerization are presented, highlighting the significant advances in this field of research.

Our society's dependency on portable electric energy, i.e., rechargeable batteries, which permit power consumption at any place and in any time, will eventually culminate in resource wars on limited commodities like lithium, cobalt, and rare earth metals. The substitution of conventional metals as means of electric charge storage by organic and polymeric materials, which may ultimately be derived from renewable resources, appears to be the only feasible way out.

In this context, the novel class of organic radical batteries (ORBs) excelling in rate capability (i.e., charging speed) and cycling stability (>1000 cycles) sets new standards in battery research. This review examines stable nitroxide radical bearing polymers, their processing to battery systems, and their promising performance.

The monomers 2-methyl-2-oxazine (MeOZI), 2-ethyl-2-oxazine (EtOZI), and 2-n-propyl-2-oxazine (nPropOZI) were synthesized and polymerized via the living cationic ring-opening polymerization (CROP) under microwave-assisted conditions. pEtOZI and pnPropOZI were found to be thermoresponsive, exhibiting LCST behavior in water and their cloud point temperatures (T_CP) are lower than for poly(2-oxazoline)s with similar side chains. However, comparison of poly(2-oxazine) and poly(2-oxazoline)s isomers reveals that poly(2-oxazine)s are more water soluble, indicating that the side chain has a stronger impact on polymer solubility than the main chain. In conclusion, variations of both the side chains and the main chains of the poly(cyclic imino ether)s resulted in a series of distinct homopolymers with tunable T_CP.

New ditopic 2,6-bis(1,2,3-triazol-4-yl)pyridine ligands featuring a π-conjugated spacer and clicked-on solubilizing groups were employed in the synthesis of Ru^II metallo-supramolecular polymers that exhibit an intense metal-to-ligand charge transfer absorption in the visible light region. The coordination polymers obtained were studied in solution by means of size exclusion chromatography and analytical ultracentrifugation, revealing a comparably high molar mass and moderate rigidity. Investigations in the solid state by atomic force and transmission electron microscopy confirmed the formation of rod-like polymers. Furthermore, film preparation by drop-casting showed good film-forming properties. Thus, the solution-processable, photoredoxactive polymers might be applicable in solar cells.

Methacrylate monomers were functionalized with a 4-hydroxythiazole chromophore and copolymerized with methyl methacrylate via RAFT. Nanoparticles of 120 and 500 nm in size were prepared without using stabilizers/surfactants. For comparative studies, preparative ultracentrifugation was applied for the separation into small and large particle fractions. All suspensions were characterized by DLS, AUC, and SEM and tested regarding their stability during centrifugation and re-suspension, autoclavation, and incubation in cell culture media. In vitro studies with mouse fibroblast cell line and differently sized NP showed a particle uptake into cells. Biocompatibility, non-toxicity, and hemocompatibility were demonstrated using a XTT assay, a live/dead staining, and an erythrocyte aggregation and hemolysis assay.

Terpyridine coordination compounds have recently revealed their potential toward optoelectronic applications, which are based on (i) their excellent charge-transfer properties or (ii) intriguing luminescence properties of the systems, depending on their design. This article features recent work in dissecting the photophysical properties of such materials by investigating the photoinduced processes in individual molecular fragments. The article starts considering the terpyridine ligands themselves before discussing the impact of metal coordination. After shedding light into the interplay of different electronic states in the terpyridine complexes, first results of a single-molecule fluorescence study are presented, which allow for correlation of the overall luminescence properties with the structure of the polymer.

For the first time, thin-film libraries of zinc(II) bis-2,2′:6′,2″-terpyridine metallopolymers are prepared by inkjet printing to study structure–property relationships and their possible usage for organic photovoltaic (OPV) or polymer light-emitting diode (PLED) applications. By using a combinatorial approach, various important parameters, including solvent system, dot spacing, and substrate temperature, as well as UV-vis absorption and emission properties, are screened in a materials efficient and reproducible manner. Homogeneous films with a thickness of 150 –200 nm were obtained when printed at 40 –50 °C and from a solvent mixture of N,N-dimethylformamide and acetophenone in a ratio of 90/10. In applications such as OPV and PLEDs the control over film thickness and homogeneity are central to obtain good device properties.

Herein, the new concept of thiol-para-fluorine “click” chemistry is employed for the formation of ruthenium(II) bisterpyridine metallopolymers in a fast and efficient manner. In general, the assembly of comparable metallopolymers requires high temperatures and long reaction times. In contrast to established methods, when utilizing a pentafluorophenyl-substituted homoleptic Ru^IIbisterpyridine complex, as a monomer, thiol-functionalized organic spacer units can easily be introduced at low temperatures and in very short reaction times. Furthermore, alternating arrangements of different metal ions (e.g., Ru^II and Fe^II) in metallopolymers can be achieved.

The incorporation of room-temperature red-emissive [Ru^II(dqp)(dqp-CH₂OH)]²⁺ (dqp is 2,6-di(quinolin-8-yl)pyridine) in poly(ϵ-caprolactone) (PCL) is explored following two routes. First, the ring-opening polymerization of ϵ-caprolactone is investigated using the free ligand and the complex as initiators. Alternatively, the complexation strategy utilizing PCL-dqp as a macroligand is detailed. Both routes yield room-temperature emissive polymers centered at 400 nm (free ligand) and 680 nm (complex) in aerated solvent. DSC and TGA showed the typical properties of PCL, for example, the melting point (59 °C).

Star-shaped poly(ϵ-caprolactone) is synthesized by ring-opening polymerization and subsequently functionalized with alkyne groups. These are utilized for the attachment of linear poly(ethylene glycol) monomethyl ether azide (mPEG-N₃) and poly(2-ethyl-2-oxazoline) azide (PEtOx-N₃) by copper-catalyzed azide-alkyne cycloaddition (CuAAC). The resulting amphiphilic star-shaped block copolymers are characterized by SEC, MALDI-TOF mass spectrometry, NMR spectroscopy, and DLS. In order to elucidate the potential of both systems as drug carriers their loading capacity is studied with a model system, the hydrophobic dye fat brown RR. Furthermore, erythrocyte aggregation tests provide first indications that the two different star-shaped block copolymers are compatible for potential applications in a biological context.

The present work addresses the synthesis and the molecular and structural characterization of soluble macromolecular architectures based on functional poly(ethylene oxide) (PEO)s and octafunctional silsesquioxanes. The synthesis of a series of functional PEOs by deactivation, decorated with allyl groups at one chain-end, was considered first. PEO star-shaped polymers were prepared by coupling via hydrosilylation of ω-allyl PEOs with octakis(hydridodimethylsiloxy)octasilsesquioxane (HMe₂SiOSiO_1.5)₈ (Q₈M₈^H), in the presence of a “Speier” catalyst. The products were characterized by SEC, ¹H NMR spectroscopy, light scattering, and MALDI–TOF MS to determine the molar masses and degree of functionalization. The star-shaped PEOs (Q₈M₈^PEO) could be isolated from the raw reaction product and characterized. A functionalization close to the theoretical value was obtained.

Poly(alkyl methacrylate) copolymers embedding bidentate trzpy chelating units as comonomer in the side chains are synthesized utilizing the controlled radical RAFT polymerization process. The free trzpy units are complexed by iron(II) and cobalt(II) ions, which results in characteristic UV-Vis absorption bands and an increase of solution viscosity. The intramolecular complexation with Co(II) ions is studied by different analytical ultracentrifugation experiments. Following the addition of a small amount of Co(II) ions, a significant decrease of the intrinsic sedimentation coefficient is observed that can be explained by the elongation of the individual polymer coils due to the electrostatic repulsion of the coordinated Co(II) ions.

A series of functionalized methacrylate monomers has been polymerized utilizing the reversible addition–fragmentation chain transfer (RAFT) polymerization procedure in order to synthesize side-chain pendant Ru(II) bis-terpyridine complexes in poly(methyl methacrylate) (PMMA) polymers by three different reaction routes. The polymers were characterized by size exclusion chromatography (SEC), ¹H NMR spectroscopy, and thermal analysis. The photophysical properties of the polymers were studied by UV-vis absorption and emission spectroscopy. Temperature dependent luminescence lifetime measurements were carried out for both monomers and polymers. In addition, cyclic voltammetry (CV) measurements were performed. All polymers revealed the typical characteristics of the Ru complex in terms of optoelectronical and electrochemical features combined with the film forming properties of a common polymer.

A systematic series of heteroleptic bis(tridentate)ruthenium(II) complexes of click-derived 1,3-bis(1,2,3-triazol-4-yl)benzene N^C^N-coordinating ligands was synthesized, analyzed by single crystal X-ray diffraction, investigated photophysically and electrochemically, and studied by computational methods. The presented comprehensive characterization allows a more detailed understanding of the radiationless deactivation mechanisms. Furthermore, we provide a fully optimized synthesis and systematic variations towards redox-matched, broadly and intensely absorbing, cyclometalated ruthenium(II) complexes. Most of them show a weak room-temperature emission and a prolonged excited-state lifetime. They display a broad absorption up to 700 nm and high molar extinction coefficients up to 20 000 M⁻¹ cm⁻¹ of the metal-to-ligand charge transfer bands, resulting in a black color. Thus, the complexes reveal great potential for dye-sensitized solar-cell applications.

The synthesis of poly(2-ethyl-2-oxazoline)-b-linear poly(ethylenimine) (PEtOx-b-LPEI) copolymers by selective basic hydrolysis of PEtOx-b-poly(2-H-2-oxazoline) (PEtOx-b-PHOx) is described. For this purpose, an easy method for the preparation of the 2-H-2-oxazoline (HOx) monomer was developed. Based on the microwave-assisted polymerization kinetics for this monomer, PEtOx-b-PHOx copolymers were prepared. Subsequently, the block copolymers were selectively hydrolyzed to PEtOx-b-LPEI under basic conditions. The success of the polymerizations and subsequent post-polymerization reactions was demonstrated by ¹H NMR spectroscopy and MALDI-TOF-MS investigations of the obtained polymers. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

A well-defined triblock terpolymer, poly(ethylene glycol)-block-poly(allyl glycidyl ether)-block-poly(tert-butyl glycidyl ether) (PEG-b-PAGE-b-Pt-BGE), with a narrow molar mass distribution has been synthesized by sequential living anionic ring-opening polymerization. Afterward, the PAGE block was modified via thiol-ene chemistry and different sugar moieties or cysteine as a model compound for peptides could be covalently attached to the polymer backbone. The solution self-assembly of the obtained bis-hydrophilic triblock terpolymers in aqueous media has been studied in detail by turbidimetry, dynamic light scattering, and transmission electron microscopy (TEM and cryo-TEM). © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

This work describes the polymerization of the free secondary amine bearing monomer 2,2,6,6-tetramethylpiperidin-4-yl methacrylate (TMPMA) by means of different controlled radical polymerization techniques (ATRP, RAFT, NMP). In particular, reversible addition-fragmentation chain transfer (RAFT) polymerization enabled a good control at high conversions and a polydispersity index below 1.3, thereby enabling the preparation of well-defined polymers. Remarkably, the polymerization of the secondary amine bearing methacrylate monomer was not hindered by the presence of the free amine that commonly induces degradation of the RAFT reagent. Subsequent oxidation of the polymer yielded the polyradical poly(2,2,6,6-tetramethylpiperidinyloxy-4-yl methacrylate), which represents a valuable material used in catalysis as well as for modern batteries. The obtained polymers having a molar mass (M_n) of 10,000–20,000 g/mol were used to fabricate well-defined, radical-bearing polymer films by inkjet- printing. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

The current investigation describes in detail the influence of the polymer molar mass as well as polymer-solvent interactions on the formation of nanoparticles using the nanoprecipitation methodology. For this purpose, a homologous series of poly(methyl methacrylate)s with molar masses ranging from 7,700 to 274,000 g mol⁻¹ was prepared. Subsequently nanoprecipitation was performed in an automated and systematic manner using liquid handling robots and a variation of different initial concentrations of the polymers and solvent/nonsolvent ratios. To elucidate information about the polymer behavior in the solvents used for the nanoprecipitation procedure (acetone, tetrahydrofuran), intrinsic viscosity measurements were performed. The nanoparticle formulations were examined in terms of particle size and size distribution, particle shape as well as zeta-potential. The conditions for the preparation of stable and uniform nanoparticles, regardless of molar mass and hydrodynamic volume of the initial polymer, were determined. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

Polymer:fullerene blends were screened in a combinatorial approach using inkjet printing thin film libraries for photovoltaic devices. The application of inkjet printing enabled a fast and simple experimental workflow from film preparation to the study of structure-property-relationships with a very high material efficiency. Inkjet printing requires less material for the preparation of thin film libraries in comparison to other dispensing techniques, like spin-coating. Two polymers (PCPDTBT, PSBTBT) and two fullerene derivatives (mono-PCBM, bis-PCBM) were investigated in various blend ratios, concentrations, solvent ratios, and film thicknesses. Morphological and optical properties of the inkjet printed films were investigated and compared with spin-coated films. This study shows the principle of an experimental setup from solution preparation to film characterization for the combinatorial investigation of large polymer:fullerene libraries.

A series of Ru^II heterodinuclear complexes of ABA-type with electron-deficient bis-terpyridines as building blocks was synthesized by (R-tpy)Ru^IIICl₃ complexation. These compounds were characterized by NMR spectroscopy, MALDI-TOF, ESI-TOF mass spectrometry, and elemental analysis. The results were compared with a coil-rod-coil Ru^II metallo-supramolecular copolymer, which was synthesized by bis-complex formation between a hydrophilic ω-terpyridine poly(ethylene glycol) Ru^IImono-complex and a hydrophobic bis-terpyridine-functionalized rigid core. This amphiphilic Ru^II triblock copolymer showed self-assembly to clusters and micelles in aqueous solution, which was studied by transmission electron microscopy and dynamic light scattering. Applying velocity sedimentation experiments the number of amphiphilic Ru^II ABA triblock copolymer molecules within the micelles could be estimated. Finally, the photophysical properties of the Ru^II supramolecular assemblies were investigated by UV–vis spectroscopy. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011

High-throughput experimentation (HTE) represents a promising and versatile approach for polyurethane (PU) research as a tool to rapidly screen and characterize a large number of samples in an automated way. To realize a unique HTE workflow for the research and development of PU elastomers (PUEs), the use of parallel automated formulation and coating platforms at Flamac were explored. To evaluate the applicability of HTE for PUEs, four different PU systems were investigated with different reactivities and viscosities. All prepared PUEs were evaluated by conventional physical testing methods measuring the E-modulus, tensile-elongation and the hardness properties revealing similar trends as conventionally prepared PUEs indicating the viability of the HTE approach. In addition, the properties of the PUEs were also investigated using downscaled microtensile bars as well as depth-sensing indentation, again, revealing similar trends. With this proof of principle study, we demonstrated for the first time that HTE can also be extended to polymeric materials based on high reactive and viscous raw materials in combination with complex technologies. The reported results provide a basis for the use of HTE approaches for preparing, screening and characterizing large numbers of PUEs for R&D purposes. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011

Two 3,6-bis(R-1H-1,2,3-triazol-4-yl)pyridazines (R=mesityl, monodisperse (CH₂CH₂O)₁₂CH₃) were synthesized by the copper(I)-catalyzed azide–alkyne cycloaddition and self-assembled with tetrakis(acetonitrile)copper(I) hexafluorophosphate and silver(I) hexafluoroantimonate in dichloromethane. The obtained copper(I) complexes were characterized in detail by time-dependent 1D [¹H, ¹³C] and 2D [¹H-NOESY] NMR spectroscopy, elemental analysis, high-resolution ESI-TOF mass spectrometry, and analytical ultracentrifugation. The latter characterization methods, as well as the comparison to analog 3,6-di(2-pyridyl)pyridazine (dppn) systems and their corresponding copper(I) and silver(I) complexes indicated that the herein described 3,6-bis(1H-1,2,3-triazol-4-yl)pyridazine ligands form [2×2] supramolecular grids. However, in the case of the 3,6-bis(1-mesityl-1H-1,2,3-triazol-4-yl)pyridazine ligand, the resultant red-colored copper(I) complex turned out to be metastable in an acetone solution. This behavior in solution was studied by NMR spectroscopy, and it led to the conclusion that the copper(I) complex transforms irreversibly into at least one different metal complex species.

Die Kupfer(I)-katalysierte Azid–Alkin Cycloaddition ermöglichte die Synthese der organischen Liganden 3,6-Bis(R-1H-1,2,3-triazol-4-yl)pyridazin (R=Mesityl, monodisperses methoxy-PEG12), die als Strukturanaloga zu 3,6-Bis(2-pyridyl)pyridazinen gesehen werden können. Diese ditopen Liganden wurden mit Tetrakis(acetonitril)kupfer(I)hexafluorophosphat und Silber(I)hexafluoroantimonat in Dichlormethan umgesetzt. Der erhaltene Kupfer(I)-Komplex wurde mittels zeitabhängiger ¹H NMR Spektroskopie, Elementaranalyse, hochauflösender Massenspektrometrie sowie analytische Ultrazentrifugation detailliert charakterisiert. Auf Grund der Ergebnisse letzterer Methoden, sowie des Vergleichs zu literaturbekannten 3,6-Bis(2-pyridyl)pyridazin Systemen kann angenommen werden, dass diese Liganden ebenfalls [2×2]-Metallgitter bilden. Weiterhin konnte mittels ¹H NMR Spektroskopie nachgewiesen werden, dass es sich im Falle des Kupfer(I)-Komplexes des Liganden 3,6-Bis(1-mesityl-1H-1,2,3-triazol-4-yl)pyridazin in Aceton um ein metastabiles System handelt, welches sich in Lösung irreversibel in mindestens eine weitere Spezies umwandelt.

The solubility behavior of well-defined poly(methyl acrylate) homopolymers as well as polystyrene-block-poly (methyl acrylate) block copolymers is discussed in this contribution. A solubility screening in ethanol–water solvent mixtures was performed in a high-throughput manner using parallel turbidimetry revealing upper critical solution temperature behavior for poly(methyl acrylate). Moreover, the self-assembly behavior of the block copolymers into micellar structures was investigated by dynamic light scattering (DLS), transmission electron microscopy (TEM), and cryo-TEM revealing upper critical solution temperature switchability of the micelles, which was evaluated by DLS at different temperatures. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011

[3+2]-cycloaddition reactions of aromatic azides and silylated alkynes in aqueous media yield 1,5-disubstituted-4-(trimethyl-silyl)-1H-1,2,3-triazoles. The formation of the 1,5-isomer is highly favored in this metal-free cycloaddition, which could be proven by 1D selective NOESY and X-ray investigations. Additionally, DFT calculations corroborate the outstanding favoritism regarding the 1,5-isomer. The described method provides a simple alternative protocol to metal-catalyzed “click chemistry” procedures, widening the scope for regioselective heavy-metal-free synthetic applications.

[3+2]-Cycloadditionen zwischen Aziden und silylierten Alkinen führen in wässrigen Lösungsmitteln zu 1,5-disubstituierten 4-(Trimethylsilyl)-1H-1,2,3-triazoles. In dieser schwermetallfreien Cycloadditions-variante ist die Bildung des 1,5-Regioisomers besonders bevorzugt. Dies konnte durch selektive NOESY-Experimente (1D) und Einkristall-Röntgendiffraktometrie bestätigt werden. Weiterhin wurde die herausragende 1,5-Regioselektivität durch DFT-Berechnungen unterstützt. Die hier be schriebene Methode stellt eine einfache Alternative zu metall-katalysierten “Click-Chemie”—Synthesewegen dar—eine 1,5-regioselektive [3+2]-Cycloaddition für schwermetallfreie Syntheseanwendungen.

The synthesis and microwave-assisted polymerization of a series of chiral 2-oxazolines with varying alkyl pendant groups, namely R-2-ethyl-4-ethyl-2-oxazoline (R-EtEtOx), R-2-butyl-4-ethyl-2-oxazoline (R-BuEtOx), R-2-octyl-4-ethyl-2-oxazoline, 2-nonyl-4-ethyl-2-oxazoline, and R-2-undecyl-4-ethyl-2-oxazoline (R-UndeEtOx), are reported. A kinetic investigation of the polymerization of R-EtEtOx revealed a living polymerization mechanism. The poly(2-oxazoline)s containing an ethyl, butyl, and octyl pendant group form similar chiral structures according to circular dichroism measurements. When the pendant group is further elongated, the chiral structure becomes more flexible in trifluoroethanol and the thermal response in hexafluoroisopropanol (HFIP) significantly changes. The short-range structure of poly-R-BuEtOx dissolved in HFIP is thermoresponsive in a complex way, due to HFIP hydrogen bonding to the polymeric amide groups, whereas the long-range structure determined from small angle neutron scattering is insensitive to temperature demonstrating that only the local secondary structure changes with temperature. In addition, the chiral structure of poly-R-UndeEtOx depends on the polarity of the solvent. The short-range structure becomes more flexible in polar solvents, most likely due to interactions with the amide groups disturbing the secondary structure. In contrast, the long-range structural transition from an ellipsoid in the apolar n-hexane to a rod structure in the polar n-butanol is ascribed to better solvation of the long aliphatic side chains. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011

The coordination compounds of the tridentate oligopyridine ligand 2,2′:6′,2′′-terpyridine (tpy) are utilized in very different fields of research, such as materials science (e.g. photovoltaics), biomedicinal chemistry (e.g. DNA intercalation), and organometallic catalysis. Applications in the latter area have arisen from initial reports on electro- or photochemical processes and, today, a broad range of reactions—from artificial photosynthesis (water splitting) to biochemical and organic transformations as well as polymerization reactions—have been catalyzed by terpyridines and their transition metal complexes. In this review, the scope and the limitations of these applications, which emerged particularly in organic and macromolecular chemistry, will be evaluated.

The electrochemical oxidation process of self-assembled monolayers formed by n-octadecyltrichlorosilane (OTS) molecules on silicon wafers has been studied in a droplet of water by means of in situ water contact angle measurements. The application of different bias voltages between the substrate and a counter electrode placed into the droplet resulted in changes of the chemical nature of the monolayer, which yielded a significant alteration of the surfaces properties. Due to the changes of the wetting properties of the monolayer during the electro-oxidation process a change in the contact angles of the water droplet is concomitantly observed. This allows the in situ monitoring of the electro-oxidation process for large modified areas of several millimeters in diameter. The chosen approach represents an easy way to screen the major parameters that influence the oxidation process. Afterwards, the oxidized regions are characterized by Fourier-transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS) measurements, and atomic force microscopy (AFM) investigations to obtain more information about the electro-oxidation process. The observations are correlated to experimental results obtained for oxidations performed on a smaller dimension range in the water meniscus of a conductive, biased AFM tip. A good correlation of the results in the different dimension ranges could be found.

2,2′:6′,2″-Terpyridines bearing well-defined π-conjugated substituents at the 4′-position are known to exhibit interesting electronic and optical properties. The systematic variation of both the spacer unit and the linker in conjugated bis(terpyridines) has resulted in a library of π-conjugated systems, enabling the study of the structure–property relationships of these materials. We have proven the Huisgen 1,3-dipolar cycloaddition reaction to be a versatile tool for connecting conjugated systems, even though the conjugation is hindered by the introduced triazole moiety. All the terpyridine derivatives were fully characterized by ¹H and ¹³C NMR spectroscopy, UV/Vis absorption and emission measurements as well as MALDI-TOF MS. Thin films of the materials were produced by spin-coating and subsequently characterized. Because tuning of the band gap of the materials over a wide range is possible, quantum yields of up to 85 % and extinction coefficients of around 100000 M^–1 cm^–1 could be observed, the compounds might be promising candidates for the design of new functional supramolecular materials.

Im stetig wachsenden Feld der Polymer-basierten Wirkstoff-Transport-Systeme gilt Poly(ethylenglycol) (PEG) als der Goldstandard für Stealth-Polymere. Welche Eigenschaften PEG aufweist, die diese herausragende Stellung rechtfertigen, soll in diesem Aufsatz diskutiert werden. Die ersten PEGylierten Produkte erschienen bereits vor 20 Jahren auf dem Markt. Seither konnten viele Erkenntnisse in klinischen Untersuchungen gewonnen werden, allerdings wurden dabei nicht nur Vorteile festgestellt, sondern auch mögliche Nebenwirkungen und Komplikationen bei der Anwendung aufgedeckt. Diese möglichen Nachteile, die eine tiefergehende Untersuchung erfordern, können in folgende Kategorien unterteilt werden: Hypersensitivität, Veränderungen der Pharmakokinetik, toxische Nebenprodukte sowie ein Abbauparadoxon, das aus der Etherstruktur resultiert: Einerseits kann das Polymer relativ einfach unter mechanischer Belastung abgebaut werden, andererseits wird jedoch ein biologischer Abbau verhindert, was bei In-vivo-Anwendungen zur Anreicherung im Körper führen kann. Der Aufsatz diskutiert diese möglichen Nachteile und stellt alternative Polymere vor.

Nitroxide-mediated radical polymerization has been used for the preparation of pentafluorostyrene (PFS) homopolymers and random copolymers of PFS and oligo(ethyleneglycol) methacrylate (OEGMA_8.5). The poly(pentafluorostyrene) homopolymers were reacted with thiophenol at different ratios at room temperature in the presence of triethylamine. The “clicked” polymers were characterized by ¹H and ¹⁹F NMR spectroscopy and size exclusion chromatography. Moreover, the copolymerization kinetics of the PFS and OEGMA_8.5 copolymers was followed, and the phase transition behavior of random copolymers with different compositions was discussed. Furthermore, copolymers of PFS and 2-(dimethylamino) ethyl methacrylate (DMAEMA) were prepared at various mole ratios, and the copolymer with a 10:90 ratio, respectively, was soluble in water at room temperature. Turbidimetry measurements were performed for PFS and OEGMA_8.5 or DMAEMA copolymers to determine their cloud points. Finally, the PFS and OEGMA_8.5 copolymer with a mole ratio of 60:40 was reacted further with thiophenol to increase the hydrophobic part in the copolymer. The cloud points of the obtained copolymers could be tuned from 87 to 33 °C by using not only the controlled radical polymerization but also the “click” reaction in a controlled fashion. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1278–1286, 2010

Nanoprecipitation represents an effective method for the production of polymeric nanoparticles. This technique was used to prepare nanoparticles from solutions of poly(methyl methacrylate) and its copolymers. Since the regulation of main parameters like particle size, particle size distribution, and molar particle mass is very important for future applications, the stable nanoparticle dispersions were examined by scanning electron microscopy, velocity sedimentation, and dynamic light scattering, whereby advantages and disadvantages of each characterization techniques are discussed. Polydispersities of particle size distributions are determined by the ratio of d_w/d_n, where d_w and d_n are weight- and number-average diameters, respectively. The particle characteristics strongly depend on the chemical structure of the polymers and the way of preparation and, therefore, vary in the studied cases in the range of 6 < d_w < 680 nm, whereas the polydispersity index d_w/d_n changes in the range of 1.02 to 1.40. It is shown that nanoparticles in a desirable size range can be prepared by solvent–nonsolvent methods (dialysis technique or dropping technique). © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3924–3931, 2010

New amphiphilic triblock copoly(2-oxazoline)s, containing hydrophobic domains with fluorine-containing blocks, were synthesized. Using microwave radiation as heating source, triblock copolymers with narrow molar mass distributions were obtained by the sequential addition of 2-ethyl-2-oxazoline, 2-(1-ethylheptyl)-2-oxazoline, and 2-(2,6-difluorophenyl)-2-oxazoline. The polymers obtained were characterized by size exclusion chromatography, ¹H NMR spectroscopy and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). To investigate the incorporation of all three monomers into the triblock copolymers, a model polymer was prepared with shorter blocks exhibiting a suitable length to be measured in the reflector mode of a MALDI-TOF MS. In addition, kinetic investigations on the homopolymerizations of all monomers were performed in nitromethane at 140 °C, yielding the polymerization rates under these conditions. DSC measurements of poly(2-(1-ethylheptyl)-2-oxazoline) and poly(2-(2,6-difluorophenyl)-2-oxazoline)) revealing glass transitions at about 33 and 120 °C, respectively. The thermal analysis of a blend of the two polymers showed two glass transitions revealing demixing, which could be an indicating for the immiscibility of the two components in the block copolymers. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010

A complete library of poly(2-oxazoline) block copolymers was synthesized via cationic ring opening polymerization for the characterization by two different soft ionization techniques, namely matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-Q-TOF MS). In addition, a detailed characterization was performed by tandem MS to gain more structural information about the block copolymer composition and its fragmentation behavior. The fragmentation of the poly(2-oxazoline) block copolymers revealed the desired polymer structure and possible side reactions, which could be explained by different mechanisms, like 1,4-ethylene or hydrogen elimination and the McLafferty +1 rearrangement. Polymers with aryl side groups showed less fragmentation due to their higher stability compared to polymers with alkyl side groups. These insights represent a further step toward the construction of a library with fragments and their fragmentation pathways for synthetic polymers, following the successful examples in proteomics. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010

In this contribution, high-throughput screening experiments are reported to study the polymerization of different aromatic polyurethane (PU) prepolymers. The prepared prepolymers were synthesized from toluene diisocyanate (T80) with different molar mass polyether diols and polyether triols, respectively. The reactions were performed in solution using a Chemspeed Accelerator™ SLT106 automated parallel synthesizer as well as in bulk to evaluate the high-throughput approach for this kind of prepolymers. More than 100 samples were prepared and characterized by GPC within 1 week labor time to investigate the reaction kinetics and to compare the resulting trends obtained by high-throughput experimentation (HTE) or by conventional, bulk prepolymerization. The synthesis of the prepared prepolymers with a linear (T80-Diol) or a branched (T80-Triol) structure followed a second-order kinetic in solution but showed deviation from this phenomenon in bulk under the selected reaction conditions, although the same trends are observed in both cases. The calculation of the rate constants allowed comparing the reactivity of different prepolymer systems, which could have a significant influence on the industrial application and processing of these materials. As a result, the HTE approach was found to represent a powerful tool for the kinetic studies of PU prepolymers. Moreover, in spite of the complexity of the curing process, the results obtained by high-throughput solution polymerization can be applied for evaluating the bulk polymerization. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 570–580, 2010

Poly(ethylene glycol) (PEG) is the most used polymer and also the gold standard for stealth polymers in the emerging field of polymer-based drug delivery. The properties that account for the overwhelming use of PEG in biomedical applications are outlined in this Review. The first approved PEGylated products have already been on the market for 20 years. A vast amount of clinical experience has since been gained with this polymer—not only benefits, but possible side effects and complications have also been found. The areas that might need consideration and more intensive and careful examination can be divided into the following categories: hypersensitivity, unexpected changes in pharmacokinetic behavior, toxic side products, and an antagonism arising from the easy degradation of the polymer under mechanical stress as a result of its ether structure and its non-biodegradability, as well as the resulting possible accumulation in the body. These possible side effects will be discussed in this Review and alternative polymers will be evaluated.

The wetting properties of structured self-assembled monolayers are used to fabricate sample target substrates for MALDI-TOF mass spectrometry. Combining the advantages of a hydrophobic-hydrophilic surface pattern and the possibility of obtaining micrometer patterns allows an increase in the sensitivity of MALDI-TOF mass spectrometry analysis and a reduction in the traceable concentration down to fmol µL⁻¹. This easy, cheap and fast patterning process provides substrates that allow sensitive, high-resolution mass spectrometry of dilute solutions.

The microwave (MW)-assisted synthesis of one dimensional carbon systems is introduced as a promising approach to improve the speed and cost-effectiveness of the fabrication process. Improved reaction conditions are generated by direct MW heating and synthesis under advanced reaction conditions. The influence of the reaction conditions is investigated and the importance of individual process parameters on the synthesis is discussed. Temperature and pressure data recorded during the irradiation process are analyzed in detail and allow the determination of essential process parameters. This leads to improved reaction conditions, better control of the one-dimensional carbon nanosystems by tuning the catalyst materials, and allows expanding this approach to initiate the synthesis on a variety of different substrates, such as quartz glass and mica.

Reversible addition-fragmentation chain transfer polymerization of trimethylsilyl-propargyl methacrylate (TMSPMA) was performed to obtain alkyne containing polymers with narrow molecular weight distributions (PDI < 1.3). Homopolymers of TMSPMA as well as random and block copolymers with methyl methacrylate were synthesized and subsequently deprotected. The obtained acetylene-functionalized polymers were further functionalized using the copper(I) catalyzed alkyne-azide cycloaddition reaction to obtain well-defined glycopolymers, grafted copolymers and anthracene-containing polymers (PDI = 1.08–1.28) that were characterized with GPC, MALDI-TOF mass spectrometry and ¹H-NMR-spectroscopy.

This article describes the synthesis and characterization of a variety of new poly(2-oxazoline)s. With regard to functional polymers, 2-oxazolines represent an interesting class of monomers because of the easy variation of the substituent in 2-position. Starting from the corresponding nitriles, different 2-oxazolines were obtained containing a diverse set of 2-substituents, including thioether bonds (M11), trifluoromethyl groups (M8, M10), and alkyl- or aryl groups (M1–M7). The subsequent polymerization of the majority of these monomers proceeded in a living manner, which was demonstrated by linear first-order kinetics, a linear increase of molar mass with conversion, and relatively narrow molar mass distributions. In addition, selected thermal and surface properties of the polymers were studied utilizing DSC and contact-angle measurements to determine the effects of different 2-substituents on the macroscopic properties. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3829–3838, 2009

High-throughput experimentation (HTE) represents a promising and versatile approach for polyurethane (PU) research as a tool to screen and characterize a large number of samples in an automated way. For the realization of a HTE workflow for PUs, the use of a Chemspeed Accelerator™ SLT106 automated parallel synthesizer was explored. To evaluate the possibility of these techniques for PUs, we studied the synthesis of prepolymers from isophorone diisocyanate and polypropylene glycol in mass and solution. Several optimization steps, transfer to solution polymerization, and downscaling prepolymerizations have been carried out in a manual way before implementing them into the Chemspeed Accelerator™. As a next step, reproducibility investigations and kinetic studies were performed in an automated manner. All experiments were evaluated by characterization with gel permeation chromatography, MALDI–TOF mass spectrometry and ¹H NMR spectroscopy. These results provide a basis to use the HTE technique for screening different PU prepolymers in the future. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3729–3739, 2009

The aim of this research was to study the effect of the initiator on the resulting monomer distribution for the cationic ring-opening copolymerization of 2-ethyl-2-oxazoline (EtOx) and 2-phenyl-2-oxazoline (PhOx). At first, kinetic studies were performed for the homopolymerizations of both monomers at 160 °C under microwave irradiation using four initiators. These initiators have the same benzyl-initiating group but different leaving groups, Cl⁻, Br⁻, I⁻, and OTs⁻. The basicity of the leaving group affects the ratio of covalent and cationic propagating species and, thus, the polymerization rate. The observed differences in polymerization rates could be correlated to the concentration of cationic species in the polymerization mixture as determined by ¹H NMR spectroscopy. In a next-step, polymerization kinetics were determined for the copolymerizations of EtOx and PhOx with these four initiators. The reactivity ratios for these copolymerizations were calculated from the polymerization rates obtained for the copolymerizations. This approach allows more accurate determination of the copolymerization parameters compared to conventional methods using the composition of single polymers. When benzyl chloride (BCl) was used as an initiator, no copolymers could be obtained because its reactivity is too low for the polymerization of PhOx. With decreasing basicity of the used counterions (Br⁻ > I⁻ > OTs⁻), the reactivity ratios gradually changed from r_EtOx = 10.1 and r_PhOx = 0.30 to r_EtOx = 7.9 and r_PhOx = 0.18. However, the large difference in reactivity ratios will lead to the formation of quasi-diblock copolymers in all cases. In conclusion, the used initiator does influence the monomer distribution in the copolymers, but for the investigated system the differences were so small that no difference in the resulting polymer properties is expected. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4804–4816, 2008

Here, we present the one-step synthesis of 2-(m-difluorophenyl)-2-oxazoline and its use as a monomer for microwave-assisted statistical cationic ring-opening copolymerizations (CROP). Well-defined amphiphilic gradient copolymers, as evidenced by the polymerization kinetics, were prepared using 2-ethyl-2-oxazoline as comonomer and methyl tosylate as initiator in nitromethane at 140 °C. The resulting gradient copolymers (DP = 60 and 100) were characterized by means of size exclusion chromatography and ¹H NMR spectroscopy. In the second part, we focus on a detailed study of the self-assembly of the copolymers in aqueous solution using atomic force microscopy and dynamic light scattering. Both methods revealed the self-assembly of the gradient copolymers into spherical micelles. To quantify the influence of the fluorine atoms and the monomer distribution on the self-assembly, a comparative study with gradient copolymers of 2-phenyl-2-oxazoline and 2-ethyl-2-oxazoline was performed. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5859–5868, 2008

Homopolymers of methacrylic acid (MAA), monoethyleneglycol methyl ether methacrylate (MEOMA), diethyleneglycol methyl ether methacrylate (MEO₂MA), oligo(ethyleneglycol) methyl ether methacrylate (OEGMA₄₇₅ and OEGMA₁₁₀₀) and oligo(ethyleneglycol) ethyl ether methacrylate (OEGEMA₂₄₆) were synthesized with various chain lengths via reversible addition fragmentation chain transfer (RAFT) polymerization. The homopolymers of MAA, MEOMA and OEGMA₁₁₀₀ did not show any cloud point (CP) in the range of 0–100 °C, whereas at a pH value of 7, the CPs were found to be 20.6, 93.7, and 20.0 °C for p(MEO₂MA), p(OEGMA₄₇₅) and p(OEGEMA₂₄₆), respectively, with an initial monomer to initiator ratio of 50. Furthermore, statistical copolymer libraries of MAA with OEGMA₄₇₅ and OEGMA₁₁₀₀ were prepared. The cloud points of the random copolymers of MAA and OEGMA₄₇₅ were found to be in the range of 20–90 °C; surprisingly, even though the homopolymers of MAA and OEGMA₁₁₀₀ did not exhibit any LCST behavior, the copolymers of these monomers at certain molar ratios (up to 40% OEGMA₁₁₀₀) revealed a double responsive behavior for both temperature and pH. Finally, the cloud points were found to be in the range of 22–98 °C, measured at pH values of 2, 4, and 7, while no cloud point was detected at pH 10. © Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7138–7147, 2008