An environmentally friendly nanoparticle-supported catalyst was successfully prepared via in situ ionic complexation between imidazolium-based polymer ionic liquid (PIL) and poly(l-prolinamide-co-MAA). The physical and chemical properties of the obtained nanoparticles were characterized by TEM, FTIR, XPS, and static water contact angle experiments. The surface properties of the nanoparticle were found to significantly affect the catalytic performance. The nanoparticle with PIL outer facilitated the adsorption of reaction substrate in it. As a result, the catalytic system catalyzed the asymmetric Aldol reaction and multicomponent reaction in pure water efficiently. The catalytic system was able to be reused and recycled five times, and with no discernible loss in catalytic activity and enantioselectivity. These findings suggest that nanoparticles based on PIL may provide a new approach for preparing high performance supported catalysts for organic reactions in water. This technology also addresses issues associated with mass transfer in pure water reactions.Keywords: Aldol reaction; in water; multicomponent reaction; nanoparticle; polymer ionic liquids;

Herein, a series of hairy microparticle-/nanoparticle-supported MacMillan was successfully synthesized by RAFT precipitation polymerization combination with surface-initiated RAFT polymerization. The research’s interest was aimed at achieving a significant enhancement of the catalytic performance which was achieved due to the changes of the polymer particle size, the molecular weight of the grafting polymer brushes, as well as the grafting polymer structure. The results showed that nanoeffect was the key to affect the catalytic activity and selectivity of catalyst system. The hairy nanoparticle had good dispersion in the reaction media and exhibited better catalytic activity and selectivity than hairy microspheres. In addition, the brush structure can be modified by grafting copolymerization with acrylamide which had the synergistic effect to effectively promote the catalyst reaction. The more significant advantages of the hairy nanoparticle-supported MacMillan were that it can effectively catalyze a representative asymmetric Diels–Alder reaction between cyclopentadiene and cinnamaldehyde in pure water and can be recycled five times while maintaining activity and selectivity.

Y-Shaped amphiphilic copolymers (zwitterionic-(PLLA2.5K)2 and MPEG-(PDLA2.5K)2) were simply synthesized through click reaction of alkyne-(PLA2.5K)2 and zwittterionic-N3 or MPEG-N3. Gel permeation chromatography (GPC) and 1H nuclear magnetic resonance (1H NMR) were employed to characterize the composition and structure of these copolymers. The stereocomplexes were prepared from pairs zwitterionic-(PLLA2.5K)2/MPEG-(PDLA2.5K)2 (molar ratio = 1:1), and confirmed by differential scanning calorimeter (DSC). Furthermore the aggregation behaviors for these synthesized polymers and their stereocomplexes had been proved by fluorescence spectroscopy (PL), transmission electron microscopy (TEM), dynamic light scattering (DLS) and static light scattering (SLS), and zeta potential. Their critical micelle concentration (CMC) obtained by PL was 0.0213 mg mL−1 for zwitterionic-(PLLA2.5K)2/MPEG1.9K-(PDLA2.5K)2 and 0.1265 mg mL−1 for zwitterionic-(PLLA2.5K)2/MPEG5K-(PDLA2.5K)2. The stereocomplexes could self-assemble into spherical micelles with diameters of 76 nm (zwitterionic-(PLLA2.5K)2/MPEG1.9K-(PDLA2.5K)2) and 89 nm (zwitterionic-(PLLA2.5K)2/MPEG5K-(PDLA2.5K)2) respectively. The biocompatibility of these copolymers and their stereocomplexes was evaluated with relatively low cytotoxicity. The DOX-loaded micelles of the stereocomplexes had a higher drug loading content and encapsulation efficiency, and could release DOX in a controlled manner. Therefore, the new stereocomplex zwitterionic-(PLLA)2/MPEG-(PDLA)2 has great potential as a hydrophobic drug nanocarrier.

Four new Y-shaped miktoarm amphiphilic copolymers were synthesized by ring-opening polymerization (ROP) and click chemistry. The structure of these copolymers was determined by nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FT-IR) and gel permeation chromatography (GPC). The stereocomplexes were prepared by an evaporation method and confirmed by FT-IR, differential scanning calorimetry (DSC) and X-ray diffraction (XRD). Further the aggregation behaviors of these synthesized polymers and their stereocomplexes were studied by fluorescence spectroscopy (PL), transmission electron microscopy (TEM) and light scattering (LS). Their critical micelle concentrations (CMC) obtained by PL were 0.005 mg mL−1 for MPEG1.9k–(scPLA4.5k)2 and 0.039 mg mL−1 for MPEG5k–(scPLA4.5k)2. The aggregation morphologies of homochiral copolymers were worm-like aggregates, while for the stereocomplexes, the spherical micelles were visually observed. The biocompatibility of these copolymers and their stereocomplexes was evaluated with relatively lower cytotoxicity. Finally, the release of doxorubicin (DOX) encapsulated into the micelles in buffer at pH 5.4 was faster than that at pH 7.4. This study demonstrates that the DOX-loaded stereocomplex micelles could be a potential carrier for cancer treatments.

Novel dumbbell-shaped amphiphilic copolymers ((PLLA)2–G1–P188–G1–(PLLA)2 and (PDLA)2–G1–P188–G1–(PDLA)2) and linear-shaped amphiphilic copolymers (PLLA–P188–PLLA and PDLA–P188–PDLA) were synthesized by click chemistry and ring opening polymerization (ROP). The stereocomplexes (scPLA)2–G1–P188–G1–(scPLA)2 and scPLA–P188–scPLA were prepared and confirmed by X-ray diffraction (XRD). The stereocomplex interaction between PLLA and PDLA was firstly analyzed using microscale thermophoresis (MST) technology and the dissociation constant (Kd) was obtained as 342 μM. The aggregation behaviors of these stereocomplexes were studied using fluorescence spectroscopy, transmission electron microscopy (TEM) and light scattering (LS). The critical aggregate concentration (CAC) obtained from fluorescence measurements was 0.021 mg mL−1 for (scPLA)2–G1–P188–G1–(scPLA)2 and 0.042 mg mL−1 for scPLA–P188–scPLA. These stereocomplexes can self-associate in aqueous solution into spherical aggregates with a diameter of 181 nm for (scPLA)2–G1–P188–G1–(scPLA)2 and 222 nm for scPLA–P188–scPLA. Furthermore, the biocompatibility of the stereocomplexes was evaluated with a relatively lower cytotoxicity. Finally, DOX was encapsulated into the stereocomplex aggregates to evaluate the drug release ability in phosphate buffer at a pH value of 7.4 or 5.4. The drug loading content and the encapsulation efficiency of the aggregates are 9.8%, 54% for (scPLA)2–G1–P188–G1–(scPLA)2 and 8.2%, 45% for scPLA–P188–scPLA. The release of DOX at pH 5.4 is faster than that at pH 7.4. The pH value has a greater effect on the release rate of DOX from dumbbell-shaped stereocomplex aggregates than that from the linear-shaped ones, which ensures the long blood circulation and the higher DOX-release surrounding the tumor site.

Two new amphiphilic linear-dendritic block copolymers (LDBCs) composed of poly(ethylene oxide) (PEO) and a dendron derived from 2,2′-bis(hydroxymethyl)propionic acid (bis-MPA), PEO(5k)-b-G3-(C18H35O2)8 and PEO(5k)-b-G3-(C2H3O2)8 were synthesized by click chemistry. The structures of the LDBCs were determined by nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FT-IR) and gel permeation chromatography (GPC). Furthermore, their aggregation behaviors at 298.15 K for these two synthesized polymers were studied by fluorescence spectroscopy and isothermal titration calorimetry (ITC). The fluorescence measurements indicate that both of the synthesized polymers have evident aggregation behavior in aqueous solution due to the significant hydrophobic interactions between the branched groups. Thus we characterized the thermodynamics of their aggregation by ITC and obtained their critical micelle concentrations (CMC), as well as the positive enthalpy of micellization for (PEO(5k)-b-G3-(C18H35O2)8), which suggests that its molecular self-assembly process is entropy-driven. Furthermore, the micellar morphologies of the copolymers in aqueous solution were verified by transmission electron microscopy (TEM) and dynamic light scattering (DLS). The spherical polymeric micelles of PEO(5k)-b-G3-(C18H35O2)8 and PEO(5k)-b-G3-(C2H3O2)8 were observed and their diameters are 70 nm and 160 nm, respectively. The length of the alkyl chain of the periphery carboxylic acid affects their CMCs and the size of micelles. Finally, the biocompatibility of both LDBCs was evaluated, and they were found to have relatively low cytotoxicity, which provides potential opportunities for a variety of biomedical applications.

Zwitterionic amphiphilic triblock copolymers bearing pendant amino acid residues poly(allyl glycidyl ether)/cysteine-b-poly(ε-caprolactone)-b-polyethylene glycol (PAGE/cys-b-PCL-b-PEG) were successfully synthesized via a combination of ring-opening polymerization (ROP), condensation reaction and click reaction. The composition and structure of these copolymers were characterized by gel permeation chromatography (GPC) and 1H nuclear magnetic resonance (1HNMR) spectroscopy. The self-assembly behavior of the copolymers was investigated by fluorescence (FL), low temperature transmission electron microscopy (cryo-TEM), dynamic light scattering (DLS) and zeta potential. The CMC was 0.20 mg mL−1 (PAGE3k/cys-b-PCL6k-b-PEG3.5k) and 0.47 mg mL−1 (PAGE1k/cys-b-PCL3k-b-PEG2k). The copolymers could self-assemble into spherical micelles with diameters of 26 nm (PAGE3k/cys-b-PCL6k-b-PEG3.5k) and 19 nm (PAGE1k/cys-b-PCL3k-b-PEG2k). Doxorubicin (DOX), an anticancer drug, was encapsulated into the micelles to evaluate the drug release ability. The biocompatibility of these copolymers was evaluated with relatively lower cytotoxicity. Therefore, these zwitterionic amphiphilic triblock copolymers are expected to emerge as promising nanocarriers for various drug deliveries.

A combination of carboxymethylpullulan (CMP) and Cu2O has been developed as a highly efficient catalytic system for the Huisgen-click reaction. Our results indicate that the acidic CMP could be used for 6 cycles without decreasing the activating efficiency for Cu2O.

In this paper, three kinds of hairy particles with different brush structures were prepared and evaluated as chiral catalysts in the direct asymmetric aldol reaction. Compared to other hairy particles, hairy particle (1) grafted with amphiphilic copolymer chains showed a good conversion rate and an outstanding enantioselectivity in pure water. The copolymer brush on the surface of hairy particle (1) contained temperature responsive poly(N-isopropylacrylamide) which underwent a coil-to-globule transition at a lower critical solution temperature (LCST). The brush formed a hydrophobic nanocavity for the organic substrates, and it provided a suitable reaction microenvironment below and above the LCST of PNIPAM. The aldol reaction was promoted by the catalytic system and it showed stable reactivity from 25 °C to 50 °C. The significant advantages of the hairy particle supported catalytic system were that it was more efficient than the corresponding homogeneous polymer supported proline, and it can be recycled five times while maintaining activity and selectivity.

An efficient protocol for Huisgen-click reaction catalyzed by Cu(OAc)2·H2O for the synthesis of 1,4-disubstituted triazoles has been developed in supercritical carbon dioxide (scCO2) in the absence of ligand at 36 °C. The protocol could afford the corresponding products in excellent yield at very low catalyst loadings (0.01 mol %).

In this paper, a simple and efficient approach for obtaining hairy particles supported proline system is described. The catalysts were synthesized by the modification of polymer microspheres via surface-initiated RAFT polymerization. Microspheres containing either carboxyl or ester groups were synthesized by RAFT precipitation copolymerization, and the functional groups influenced the yield and asymmetric selectivity of chiral product in different DMF–H2O solvents during a representative aldol reaction. Compared with hairy particles 2 with ester groups, hairy particles 1 with carboxyl groups exhibited better catalytic activity and asymmetric selectivity, providing more suitable microenvironments for the aldol reaction. Importantly, the hairy particles 1, as catalyst, can be easily recovered and recycled, and show no significant loss of activity and selectivity after 6 cycles. The application of RAFT precipitation polymerization together with the facile surface-grafting approach provides a general and promising way for chiral catalyst load.

•The method to synthesize PLA-b–PHMTYO-b–PLA is relatively facile and efficient.•PLA-b–PHMTYO-b–PLA self-assembles into spherical micelles with low CMC in water.•PLA-b–PHMTYO-b–PLA exhibits better biocompatibility and biodegradability.Novel amphiphilic block copolymers bearing pendant hydroxyl groups polylactide-b–poly(3,3-bis(Hydroxymethyl–triazolylmethyl) oxetane)-b–polylactide (PLA-b–PHMTYO-b–PLA) were synthesized via a facile and efficient method. First, the block copolymer intermediates polylactide-b–poly(3,3-Diazidomethyloxetane)-b–polylactide (PLA-b–PBAMO-b–PLA) were synthesized through ring-opening polymerization of lactide using PBAMO as a macroinitiator. Following “Click” reaction of PLA-b–PBAMO-b–PLA with propargyl alcohol provided the targeted amphiphilic block copolymers PLA-b–PHMTYO-b–PLA with pendant hydroxyl groups. The composition and structure of prepared copolymers were characterized by 1H nuclear magnetic resonance (1H NMR) spectroscopy, Fourier transform infrared (FT-IR) and gel permeation chromatography (GPC). The self-assembly behavior of the copolymers in water was investigated by transmission electron microscope (TEM), dynamic light scattering (DLS) and static light scattering (SLS). The results showed that the novel copolymers PLA-b–PHMTYO-b–PLA self-assembled into spherical micelles with diameters ranging from 100 nm to 200 nm in aqueous solution. These copolymers also exhibited low critical micellar concentrations (CMC: 6.9 × 10− 4 mg/mL and 3.9 × 10− 5 mg/mL, respectively). In addition, the in vitro cytotoxicity of these copolymers was determined in the presence of L929 cells. The results showed that the block copolymers PLA-b–PHMTYO-b–PLA exhibited better biocompatibility. Therefore, these well-defined copolymers are expected to find some applications in drug delivery or tissue engineering.