Three model polythiophenes, PTCBT, PTCFBT and PFTCBT, have been synthesized to investigate the effect of fluorination on photovoltaic performance of polythiothenes. Compared with PTCBT, PFTCBT with F atom on TC unit shows a narrower optical bandgap (1.79 eV), higher crystallinity, and ideal morphology in the active layer, leading to a higher short-circuit current density (Jsc) of 11.84 mA/cm2 and a power conversion efficiency (PCE) of 5.93%. The lock-up function of fluorine enhances polythiophene backbone planarity and molecular packing.

A multi-responsive supramolecular polymer, β-CD-(PNIPAAm)4-Azo-(PMAA)7, is demonstrated here. This amphiphilic polymer can be achieved by altering the pH or temperature of a solution of the supramolecular polymer system. Absorption and emission spectroscopy, solution transmittance, dynamic light scattering (DLS), and transmission electron microscopy (TEM) were applied. It was found that β-CD-(PNIPAAm)4-Azo-(PMAA)7 can self-assemble into inverse spherical polymeric nanoaggregates and can then disassemble reversibly under the irradiation of UV light due to the trans-to-cis isomerization of the azo groups. The resulting supramolecular polymer is demonstrated to have useful properties, including self-aggregation, supramolecular gelation and stimulus-responsive behavior.

Magnetic polymer microsphere is a kind of hybrid microsphere composed of polymer and inorganic magnetic particles. The materials have potential applications in biomedicine, catalysis, sewage treatment, etc. The objective of this paper was to develop a targeted anticancer drug delivery system based on carboxymethyl chitosan-coated Fe3O4/SiO2 hollow microspheres (HMS-CMCS) combining receptor-mediated targeting and magnetic targeting. The binding of chitosan to the surface of modified Fe3O4/SiO2 hollow microspheres could effectively prevent them from fusing with one another and undesirable payload release in regular storage or physiological environments. The synthesized HMS-CMCS microspheres could completely release the CDDP which was used as a model drug. The obtained HMS-CMCS had the hollow structure, and the walls of the HMS-CMCS had numerous micropores with a broad distribution of approximately 1 nm. The composite particles were characterized by TEM, FT-IR, and VSM. The results showed that the microspheres had an average size of 400 nm. The fabricated material is thus proposed as a biological material for drug delivery.

Pectinase was covalently immobilized onto the macroporous polyacrylamide (PAM) microspheres synthesized via an inverse suspension polymerization approach, resulting in 81.7% immobilization yield. The stability of the macroporous PAM support, which has a large surface area, is not impeded by the adsorbed proteins despite the fact that up to 296.3 mg of enzyme is immobilized per gram of the carrier particles. The immobilized enzyme retained more than 75% of its initial activity over 30 days, and the optimum temperature/pH also increased to the range of 50−60 °C/3.0−5.0. The immobilized enzyme also exhibited great operational stability, and more than 75% residual activity was observed after 10 batch reactions. The kinetics of a model reaction catalyzed by the immobilized pectinase was finally investigated. Moreover, the immobilized pectinase could be recovered by centrifuging and showed durable activity at the process of recycle.

Pectinase was immobilized onto thermo-sensitive amphiphilic block copolymers poly(styrene-b-Nisopropylacrylamide) PS-b-poly(N-isopropylacrylamide) (PNIPAM) by covalent attachment. Biochemical studies have found that the stability of the PS-b-PNIPAM support is not impeded by the bound proteins despite that up to 242.5 mg of enzyme is immobilized per gram of carrier particles. The immobilized enzyme retained nearly 65% of its initial activity over 30 days, and the optimum temperature and pH also increased to the range of 60 ∼ 70°C and 4.0 ∼ 6.0, respectively. The immobilized enzyme also exhibited great operational stability, and more than 60% residual activity was observed in the immobilized enzyme after 10 batch reactions. Moreover, the lower critical solution temperature of the PS-b-PNIPAM support could be switched on or off by a small change in solution temperature. Thus, the immobilized pectinase could be recovered and showed durable activity during the recycle process.

Polymer nanocomposite microspheres (PNCMs) as solid supports can improve the efficiency of immobilized enzymes by reducing diffusional limitation as well as by increasing the surface area per mass unit. In this work, pectinase was immobilized on Fe3O4/SiO2-g-poly(PSStNa) nanocomposite microspheres by covalent attachment. Biochemical studies showed an improved storage stability of the immobilized pectinase as well as enhanced performance at higher temperatures and over a wider pH range. The immobilized enzyme retained >50% of its initial activity over 30 days, and the optimum temperature and pH also increased to the ranges of 50−60 °C and 3.0−4.7, respectively. The kinetics of a model reaction catalyzed by the immobilized pectinase was finally investigated by the Michaelis−Menten equation. The PSStNa support presents a very simple, mild, and time-saving process for enzyme immobilization, and this strategy of immobilizing pectinase also makes use of expensive enzymes economically viable, strengthening repeated use of them as catalysts following their rapid and easy separation with a magnet.

Functionalized Fe3O4 nanoparticles decorated with silica and chitosan have been prepared via two steps in this paper. The first step involved magnetite nanoparticles (Fe3O4) homogeneously incorporated into silica spheres using the modified Stöber process. Second, the silica-coated Fe3O4 nanoparticles were covered with the outer shell of cationic polyelectrolyte chitosan by a layer-by-layer assembly process. X-ray diffraction results indicated that the surface-modified Fe3O4 nanoparticles did not lead to phase change compared with the pure Fe3O4. Transmission electron microscopy studies revealed nanoparticles remained monodisperse, and silica shells have trapped more than one magnetic core. Average particle sizes of chitosan-coated Fe3O4/SiO2 microspheres are about 80–100 nm. In addition, super-paramagnetic properties of hybrid microspheres have also been detected by a vibrating-sample magnetometer. It may make the hybrid microspheres of important use in mild separation, enzyme immobilization, etc.

Herein we report on the production of composite core–shell particles, which are actually self-assembly of poly (N-isopropylacrylamide)-based amphiphilic block copolymers as a template for metal-block copolymer nanocomposites formation. Organic–inorganic composites were prepared with Ag nanoparticles embedded within colloidal particles of an amphiphilic, thermally responsive polymer. To promote the incorporation of unaggregated Ag nanoparticles, temperature responsive microspheres of poly (N-isopropylacrylamide) (NIPAM) block with polystyrene were synthesized. Polyethyleneimine (PEI) could act as the linker between Ag ions (Ag nanoparticles) and poly (styrene-b-N-isopropylacrylamide) (PS-b-PNIPAM) colloids and the reducing agent in the formation of Ag nanoparticles. Transmission electron microscopy (TEM) measurements confirmed the nanostructures, 1HNMR and FTIR characterized the components of the resulting nanoobjects. These stimuli-responsive hybrid microspheres will have potential applications in biomedical areas, such as tissue engineering and drug delivery.

Block copolymer-supported Ag Nps (nanoparticles) have either a “cherry”-like or “raspberry”-like morphology [Antonietti, et al., Adv. Mater. 7 (1995) 1000–1005] depending on the amount of silver nitrate loading and the external conditions. Sonication favors silver nitrate and polyethyleneimine diffusion; the nucleation sites are well distributed in the micellar cores, so it is easy to form the cherry-like Ag NP colloids. However, when the amount of silver nitrate is decreased, it is heating that induces the formation of raspberry-like Ag NP colloids. The Ag NP colloids were investigated by transmission electron microscopy to demonstrate the nanosize dimensions and the location of the Ag NPs in the micelles. X-ray diffraction was employed to determine the crystal structure of the Ag NPs. UV–vis spectroscopy was employed for further qualitative characterization of the optical properties of Ag NPs.By changing the level of silver nitrate loading and the external conditions, “cherry”- or “raspberry”-like silver nanoparticles can be produced.

This article reports the synthesis of the poly(sodium 4-styrenesulfonate)-grafted Fe3O4/SiO2 particles via two steps. The first step involved magnetite nanoparticles (Fe3O4) homogeneously incorporated into silica spheres using the modified Stöber method. Second, the modified silica-coated Fe3O4 nanoparticles were covered with the outer shell of anionic polyelectrolyte by surface-initiated atom transfer radical polymerization. The resulted composites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive microscopy (EDS), Fourier transform-infrared (FT-IR), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and vibration sample magnetometer (VSM). The XRD results indicated that the surface modified Fe3O4 nanoparticles did not lead to phase change compared with the pure Fe3O4. TEM studies revealed nanoparticles remained monodisperse. The detection of sulfur and sodium signals was a convincing evidence that sodium 4-styrenesulfonate was grafted onto the surface of the magnetic silica in XPS analysis. Finally, super-paramagnetic properties of the composite particles, and the ease of modifying the surfaces may make the composites of important use in mild separation, enzyme immobilization, etc.Fig. 2b shows TEM images of silica-coated Fe3O4 particles. The magnetic silica particles with well-defined core/shell structures were rather monodisperse, even though silica shells have trapped more than one magnetic core. The Fe3O4/SiO2 particles used in this case for the production of composite particles had an average diameter of 70±10 nm obtained by TEM images.Figure optionsDownload full-size imageDownload as PowerPoint slide

Novel spherical assemblies of ZnSe-containing block copolymer reverse micelles in aqueous solution have been formed by the addition of HSe-solution to mixtures of Zn2+and the reverse micelles soft template Polyacrylonitrile-block-poly (ethylene glycol)-block-Polyacrylonitrile. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and UV-Vis spectrometer. The results of XRD and TEM analyses demonstrated that the products were spherical and homogeneous with cubic structure, which are about 60 nm in diameter. The corresponding UV-Vis absorption peaks showed a blue shift compared to bulk ZnSe. From the position of the absorption edge (λe), we calculate an actual ZnSe particle diameter of ~ 5.0 nm. This approach represented a simple method in the synthesis of the polymer micelles shelled with inorganic materials based on using amphiphilic block copolymers. And studies to improve the uniformity of size, shape, and crystal domain will be a focus of future work.

A solution-phase route was devised to synthesize crystal Ag nanowires with the micellar in-situ of Ag+. Ag nanocrystals were synthesized by using amphiphilic block copolymer polystyrene-block-poly (acrylic acid) (PS–b–PAA) based on the flexibility of the copolymer chains and the complex effect of –COOH in the poly acrylic acid with Ag+ ion and Ag under ultrasonic irradiation. The crystal morphologies were changing from rods to dendrite crystals. The resultant nanoproducts were characterized by transmission electron microscope (TEM), X-ray diffraction (XRD) and electron diffraction (ED). The results revealed that the size of the resulting Ag nanostructures prepared was strongly dependent on the initial concentration of the silver ion solution and the concentration of the copolymer. This work provides a simple route for the in situ synthesis of Ag nanostructures.

In this paper, we used the PS-cored aggregates with PAA corona as a template for metal-block copolymer nanocomposites formation. Polyethyleneimine (PEI) could act as the linker between Ag ions (Ag nanoparticles) and PS-b-PAA colloids and the reducing agent in the formation of Ag nanoparticles. The product was characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and UV–vis spectrum. The results revealed that the size and size distribution of the resulting silver nanoparticles prepared based on the copolymer were strongly dependent on the ratio of initial concentration of the silver ion solution to copolymer. The silver crystal was polycrystalline with a face-centered cubic structure, as confirmed by XRD. This work provides a simple route for the in situ synthesis of Ag nanoparticles on block copolymer colloids.

This paper describes a new strategy through noncovalent functionalization of multi-walled carbon nanotubes (MWNTs) by a kind of new copolymer Polyethyleneimine-graft-Polyacrylonitrile for attaching CdSe nanoparticles onto the MWNTs to fabricate Carbon Nanotube/CdSe heterostructures. Polyethyleneimine (PEI), an amino-rich cationic polyelectrolyte, can interact with the MWNTs through electrostatic interaction. Then, CNT/PEI-g-PAN was successfully prepared by in situ atom transfer radical polymerization (ATRP), which did not introduce defects to the structure of CNTs. Thus, CdSe nanoparticles can be covalently coupled to functionalized carbon nanotubes (CNTs) in a uniform and controllable manner. Moreover, this method ensures good dispersion and high stability in any commonly used organic or inorganic solvent. In this manner, our strategy allows the attachment of various colloidal nanoparticles to CNTs, independent of their surface properties, i.e. hydrophilic or hydrophobic. TEM, XRD, EDS and FT-IR are all used to characterize the CNT/CdSe composite materials. In addition, the optical properties are investigated by UV–vis spectrum.

“Spherical polyelectrolyte brush” of core–shell structure were prepared by grafting poly (sodium 4-styrenesulphonate) (PSStNa) from SiO2 nanoparticle via the surface-initiated atom transfer radical polymerization strategy. The colloidal stability was not impeded by the adsorbed proteins despite the fact that up to 316.8 mg of enzyme was adsorbed per gram of the carrier particles. The immobilized pectinase revealed acceptable pH stability over a broad experimental range of 3.0–4.5. The activity half lives for native and bound states of enzyme were found as 13.5 d and 30 d, respectively. The activity of immobilized pectinase adsorbed onto these particles was analyzed in terms of the Michaelis–Menten parameters. Kinetic parameters were calculated as 8.28 and 9.98 g pectin ml−1 for Km and 1.165 × 10−3 g pectin s−1 g enzyme−1 1.124 × 10−3 g pectin s−1 g particle−1 for Vmax in the case of free and immobilized enzymes, respectively. Enzyme activity was found to be approximately 49.7% for immobilized enzyme after storage for 1 month.

The idea of preparing the surface of Fe3O4 layer preadsorbed on the “spherical polyelectrolyte brush” via layer-by-layer self-assembly approach receives special relevance in enzyme technology. “Spherical polyelectrolyte brush” of core–shell structure were prepared by grafting poly(sodium 4-styrenesulphonate) (PSStNa) from SiO2 nanoparticles via the surface-initiated atom transfer radical polymerization strategy. The silica-coated (PEI/Fe3O4)n support presents a very simple, mild, and time-saving process for enzyme immobilization. The kinetics of a model reaction catalyzed by the immobilized pectinase was finally investigated by the Michaelis–Menten equation. These particles, premodified with the layer of magnetic nanoparticles to impart a magnetic property and subsequently coated with polyelectrolyte multilayer, were repeatedly used as catalysts following their rapid and easy separation with a magnet. Besides simplicity and versatility, the ease of enzyme regeneration constitutes an additional benefit of this approach.

Polymer nanocomposites of core–shell structure were prepared by grafting poly(tert-butyl acrylate) (Pt-BA) from SiO2 nanoparticle via the surface-initiated polymerization (SIP) strategy. This new organic inorganic hybrid particle has been extensively characterized by XPS (X-ray Photoelectron Spectroscopy), SEM (Scanning Electron Microscopy), TEM (Transmission Electron Microscopy), and TGA (ThermoGravimetric Analysis).

Silver nanoparticles were synthesized by using amphiphilic block copolymer Polyacrylonitrile-block-poly(ethylene glycol)-blcok-Polyacrylonitrile (PAN-b-PEG-b-PAN, PEA) based on the flexibility of the copolymer chains and the complex effect of –CN in the polyacrylonitrile with Ag+ ion and Ag under ultrasonic irradiation. The product was characterized by X-ray Diffraction (XRD), Fourier Transfer Infrared Spectrometer (FTIR), Transmission Electron Microscope (TEM), UV–Vis spectrum and Thermal Gravity Analysis (TGA). The results revealed that the size and size distribution of the resulting silver nanoparticles prepared basing on the copolymer were strongly dependent on the initial concentration of the silver ion solution and the irradiation conditions. Low initial silver ion concentration allowed for yielding silver nanoparticles with a small size and the size of the silver nanoparticles increased with increasing of silver ion concentration. The silver crystal was polycrystalline with a cubic structure, as confirmed by XRD. This work provides a simple route for the in situ synthesis of Ag nanoparticles.

Well-defined amphiphilic block copolymers poly(styrene-b-acrylic acid) (PS-b-PAA) with controlled block length were synthesized using atom transfer radical polymerization (ATRP). Pectinase enzyme was immobilized on the well-defined amphiphilic block copolymers PS-b-PAA. The carboxyl groups on the amphiphilic PS-b-PAA diblock copolymers present a very simple, mild, and time-saving process for enzyme immobilization. Various characteristics of immobilized pectinase such as the pH and temperature stability, thermal stability, and storage stability were valuated. Among them the pH optimum and temperature optimum of free and immobilized pectinase were found to be pH 6.0 and 65 °C.