Hollow mesoporous silica nanoparticles modified with coumarin‐containing copolymer for photo‐modulated loading and releasing guest molecule

Hollow mesoporous silica nanoparticles (HMSNs) grafted with a photo‐responsive copolymer containing coumarin groups were successfully prepared. With uniform polystyrene nanoparticles and cetyltrimethylammonium bromide correspondingly as the template of core and channel, HMSNs were made from tetraethyloxysilane in alkalic condition. Epoxy groups were introduced onto the outer surface of HMSNs with γ‐(2,3‐epoxypropoxy)propyltrimethoxysilane and converted into azido groups with sodium azide, resulting in azido‐functionalized HMSNs (azido‐HMSNs). Meanwhile, single‐electron transfer‐living radical copolymerization of methyl methacrylate (MMA) and 7‐(2‐methacryloyloxy)‐4‐methylcoumarin (CMA) with propargyl 2‐bromoisobutyrate as the initiator produced alkynyl‐capped P(MMA‐co‐CMA) [alkynyl‐P(MMA‐co‐CMA)]. Finally, photo‐responsive HMSNs grafted with P(MMA‐co‐CMA) [HMSN‐g‐P(MMA‐co‐CMA)] was achieved through the click reaction between azido‐HMSNs and alkynyl‐P(MMA‐co‐CMA). Different techniques such as transmission electron microscopy, Fourier transform infrared spectroscopy, and thermal gravimetric analysis confirmed the successful preparation of the resultant hybrid nanoparticles and their intermediates. Because of its hollow core, mesoporous shell channels and light responsiveness, the coumarin‐modified HMSNs would be an interesting nano‐vehicle for guest molecules. Thus, the loading and release of pyrene with HMSN‐g‐P(MMA‐co‐CMA) was studied. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 3791–3799     

Preparation and ion conductivities of the plasticized polymer electrolytes based on the poly(acrylonitrile‐ co‐lithium methacrylate)

The polymer electrolytes composed of poly(acrylonitrile‐co‐lithium methacrylate) [P(AN‐co‐LiMA)], ethylene carbonate (EC), and LiClO₄ salts have been prepared. The ion groups in the P(AN‐co‐LiMA) were found to prevent EC from crystallization through their ion–dipole interactions with the polar groups in the EC. This suppression of the EC crystallization could lead to the enhancement of the ion conductivity at subambient temperature. The polymer electrolytes based on the PAN ionomer with 4 mol % ion content exhibited ion conductivities of 2.4 × 10⁻⁴ S/cm at −10°C and 1.9 × 10⁻³ S/cm at 25°C by simply using EC as a plasticizer. In the polymer electrolytes based on the PAN ionomer, ion motions seemed to be coupled with the segmental motions of the polymer chain due to the presence of the ion–dipole interaction between the ion groups in the ionomer and the polar groups in the EC, while the ion transport in the PAN‐based polymer electrolytes was similar to that of the liquid electrolytes. © 1999 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 37: 247–252, 1999     

Graphene oxide sheet–polyaniline nanohybrids for enhanced photovoltaic performance of dye‐sensitized solar cells

In this study, photovoltaic (PV) properties of dye‐sensitized solar cells (DSSCs) incorporated with graphene oxide nanosheet‐polyaniline (GOS‐PANI) nanohybrid/poly(ethylene oxide) (PEO) blend gel electrolytes were investigated. Chemical structure and composition of GOS‐PANI nanohybrids were characterized by Raman spectroscopy and X‐ray photoelectron spectroscopy. The images of transmission electron microscopy revealed that PANI nanorods were anchored to the single‐layered GOS for the GOS‐PANI nanohybrids. Ionic conductivities of the GOS‐PANI/PEO–based gel electrolytes were measured using a conductivity meter. The electrochemical catalytic activities of the GOS‐PANI nanohybrids were determined through cyclic voltammetry. These GOS‐PANI nanohybrids were served as the extended electron transfer materials and catalyst for the electrochemical reduction of I₃^?. Due to the enhancement of the ionic conductivity and electrochemical catalytic activity of the gel electrolyte, better PV performance was observed for the DSSCs based on the GOS‐PANI containing electrolytes as compared to the pristine PEO electrolyte‐based DSSC sample. Moreover, PV performances of the GOS‐PANI/PEO–based DSSCs were closely related to the PANI content of GOS‐PANI nanohybrids. The highest photo‐energy conversion efficiency (5.63%) was obtained for an optimized GOS‐PANI/PEO (5:95, w/w) blend gel electrolyte‐based DSSC sample. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014 , 52, 321–332     

Synthesis and characterization of poly (1‐vinyl‐3‐butylimidazolium‐co‐methyl methacrylate) gel polymer electrolytes for dye‐sensitized solar cells: Effect of structure and composition

Herein, three ionic liquid random copolymers (P) containing 1‐vinyl‐3‐butylimidazolium bromide (VBImBr) and methyl methacrylate (MMA) with various molar ratios were prepared using conventional free radical polymerization. Afterward, their corresponding chemically cross‐linked copolymers (XP) were formed similarly in the presence of polyethylene glycol dimethacrylate (PEGDMA). The synthesized copolymers were characterized using FT‐IR, ¹H NMR, and GPC. Differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) results showed that the rigidity and thermal stability of the copolymers depended on the ionic liquid content as well as the degree of cross‐linking. Gel polymer electrolytes were then prepared via obtained copolymers in the presence of a constant amount of synthesized imidazolium‐based ionic liquid. Among the copolymers, the P3 with in feed VBImBr:MMA molar ratio of 70:30 and the cross‐linked 1%‐XP3 copolymer prepared with 1 mol% of PEGDMA exhibited the highest conductivity and diffusion coefficients for I₃^¯ and I^¯. The power conversion efficiency of the optimized linear and cross‐linked copolymers (P3 and 1%‐XP3) under the simulated AM 1.5 solar spectrum irradiation at 100 mW cm^?2 were 3.49 and 4.13% in the fabricated dye‐sensitized solar cells (DSSCs), respectively. The superior long‐term stability and high performance of the gel electrolyte containing 1%‐XP3 suggested it as commercial gel electrolyte for future DSSCs.     

Preparation of a copolymer of methyl methacrylate with a new monomer, 2,2,6,6‐tetramethyl‐4‐benzyloxyl‐piperidinyl methacrylate,and its initiation of the graft copolymerization of styrene with a controlled radical mechanism

A copolymer [P(MMA‐co‐TBPM)] was prepared by the radical polymerization of methyl methacrylate (MMA) and 2,2,6,6‐tetramethyl‐4‐benzyloxyl‐piperidinyl methacrylate (TBPM) with azobisisobutyronitrile as an initiator. TBPM was a new monomer containing an activated ester. Both the copolymer and TBPM were characterized with NMR, IR, and gel permeation chromatography in detail. It was confirmed that P(MMA‐co‐TBPM) could initiate the graft polymerization of styrene by the cleavage of the activated ester of the TBPM segment. This process was controllable, and the molecular weight of the graft chain of polystyrene increased with the increment of conversion. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4398–4403, 2002     

Enhancement of photocurrent of polymer‐gelled dye‐sensitized solar cell by incorporation of exfoliated montmorillonite nanoplatelets

Poly(n‐isopropylacrylamide) (PNIPAAm) and its nanocomposite with exfoliated montmorillonite (MMT) were prepared by soap‐free emulsion polymerization and individually applied to gel the electrolyte systems for the dye‐sensitized solar cells (DSSCs). Each exfoliated MMT nanoplatelet had a thickness of ～ 1 nm, carried ～ 1.8 cation/nm², and acted like a two‐dimensional electrolyte. The DSSC with the LiI/I₂/tertiary butylpyridine electrolyte system gelled by this polymer nanocomposite had higher short‐circuit current density (J_sc) compared to that gelled by the neat PNIPAAm. The former has a J_sc of 12.6 mA/cm², an open circuit voltage (V_oc) of 0.73 V, and a fill factor (FF) of 0.59, which harvested 5.4% electricity conversion efficiency (η) under AM 1.5 irradiation at 100 mW/cm², whereas the latter has J_sc = 7.28 mA/cm², V_oc = 0.72 V, FF = 0.60, and η = 3.17%. IPCE of the nanocomposite‐gelled DSSC were also improved. Electrochemical impedance spectroscopy of the DSSCs revealed that the nanocomposite‐gelled electrolytes significantly decreased the impedances in three major electric current paths of DSSCs, that is, the resistance of electrolytes and electric contacts, impedance across the electrolytes/dye‐coated TiO₂ interface, and Nernstian diffusion within the electrolytes. The results were also consistent with the increased molar conductivity of nanocomposite‐gelled electrolytes. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 47–53, 2008     

A minimal amount of acrylonitrile turns the nitroxide‐mediated polymerization of methyl methacrylate into an almost ideal controlled/living system

Nitroxide‐mediated controlled/living free‐radical polymerization of methyl methacrylate initiated by the SG1‐based alkoxyamine BlocBuilder was successfully performed in bulk at 80–99 °C with the help of a very small amount of acrylonitrile (AN, 2.2–8.8 mol %) as a comonomer. Well‐defined PMMA‐rich P(MMA‐co‐AN) copolymers were prepared with the number‐average molar mass, M_n, in the 6.1–32 kg mol^?1 range and polydispersity indexes as low as 1.24. Incorporation of AN in the copolymers was demonstrated by ¹H and ¹³C NMR spectroscopy, and its effect on the chain thermal properties was evaluated by DSC and TGA analyses. Investigation of chain‐end functionalization by an alkoxyamine group was performed by means of ³¹P NMR spectroscopy and chain extensions from a P(MMA‐co‐AN)‐SG1 macroinitiator. It demonstrated the very high proportion of SG1‐terminated polymer chains, which opened the door to block copolymer synthesis with a high quality of control. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 34–47, 2010     

The suzuki–heck polymerization as a tool for the straightforward obtainment of poly(fluorenylene‐vinylene) sensitizers for dye‐sensitized solar cells

This article describes the synthesis and properties of the first poly(arylene‐vinylene)‐based sensitizers for application in dye‐sensitized solar cells (DSSC). The polymers were prepared by the Suzuki–Heck copolymerization of potassium vinyltrifluoroborate (PVTB) with a mixture of dibromoaryl comonomers designed to obtain macromolecules able to bind onto the photoelectrode by means of carboxyphenylene units. The copolymerization reactions were carried out in the presence of an excess of PVTB to lower the molecular weights of the polymers, which were obtained as soluble materials. The polymers poly[(9,9‐didodecyl‐2,7‐fluorenylene)‐vinylene‐co‐(carboxy‐2,5‐phenylene)‐vinylene] ( P1 ), poly[(9,9‐didodecyl‐2,7‐fluorenylene)‐vinylene‐co‐(carboxy‐2,5‐phenylene)‐vinylene‐co‐(4,7‐benzothiadiazolylene)‐vinylene] ( P2 ), and poly[(9,9‐didodecyl‐2,7‐fluorenylene)‐vinylene‐co‐(carboxy‐2,5‐phenylene)‐vinylene‐co‐2,5‐thienylene‐vinylene] ( P3 ) were used in DSSC devices, obtaining conversion efficiencies up to 0.88% ( P3 ). © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Polymer electrolyte membranes by in situ polymerization of poly(ethylene carbonate‐co‐ethylene oxide) macromonomers in blends with poly(vinylidene fluoride‐co‐hexafluoropropylene)

Salt‐containing membranes based on polymethacrylates having poly(ethylene carbonate‐co‐ethylene oxide) side chains, as well as their blends with poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP), have been studied. Self‐supportive ion conductive membranes were prepared by casting films of methacrylate functional poly(ethylene carbonate‐co‐ethylene oxide) macromonomers containing lithium bis(trifluorosulfonyl)imide (LiTFSI) salt, followed by irradiation with UV‐light to polymerize the methacrylate units in situ. Homogenous electrolyte membranes based on the polymerized macromonomers showed a conductivity of 6.3 × 10^?6 S cm^?1 at 20 °C. The preparation of polymer blends, by the addition of PVDF‐HFP to the electrolytes, was found to greatly improve the mechanical properties. However, the addition led to an increase of the glass transition temperature (T_g) of the ion conductive phase by ～5 °C. The conductivity of the blend membranes was thus lower in relation to the corresponding homogeneous polymer electrolytes, and 2.5 × 10^?6 S cm^?1 was recorded for a membrane containing 10 wt % PVDF‐HFP at 20 °C. Increasing the salt concentration in the blend membranes was found to increase the T_g of the ion conductive component and decrease the propensity for the crystallization of the PVDF‐HFP component. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 79–90, 2007     

Crosslinking polymerization leading to interpenetrating polymer network formation. II. Polyaddition crosslinking reactions of poly(methyl methacrylate‐co‐2‐methacryloyloxyethyl isocyanate) with various diols

As part of our continuing studies concerned with the elucidation of the crosslinking polymerization mechanism leading to interpenetrating polymer network (IPN) formation, in which IPNs consist of both polymethacrylates and polyurethane (PU) networks, this article explores the polyaddition crosslinking reactions of multifunctional poly(methyl methacrylate‐co‐2‐methacryloyloxyethyl isocyanate) [poly(MMA‐co‐MOI)] [MMA/MOI = 90/10] with various diols leading to PU network formation. Thus, the equimolar polyaddition crosslinking reactions of poly(MMA‐co‐MOI) with ethylene glycol (EG), 1,6‐hexane diol, and 1,10‐decane diol (DD) were carried out in N‐methyl pyrrolidone at a 0.25 mol/L isocyanate group concentration at 80 °C. The second‐order rate constants decreased from EG to DD. The deviation of the actual gel point from the theoretical one was smaller from EG to DD. The intrinsic viscosity of resulting prepolymer demonstrated almost no variation with progressing polymerization for the EG system, whereas it gradually increased with conversion for the DD system. Close to the gel point conversion it increased rather drastically for both systems. The swelling ratio of resulting gel was higher from EG to DD. These are discussed mechanistically in terms of the significant occurrence of intramolecular cyclization and intramolecular crosslinking reactions leading to shrinkage of the molecular size. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3243–3248, 2003     

Grafting of polymer matrix to exfoliated montmorillonite nanoplatelets in nanocomposite film cast from soap‐free emulsion polymerized latex and its fortified mechanical properties

Poly(methyl acrylate‐co‐methyl methacrylate) [P(MA‐co‐MMA)] nanocomposite film containing 1 wt % of montmorillonite (MMT) exhibited unusual higher ductility, higher strain recovery ratio after creep, and higher modulus and strength compared to neat P(MA‐co‐MMA) as they were cast from their individual latices fabricated by soap‐free emulsion polymerization. The fortified mechanical properties were attributed to the MgO components of exfoliated MMT nanoplatelets being grafted by P(MA‐co‐MMA) chains as verified by FTIR and XPS spectroscopies, which to the best of our knowledge is the first time in the literature providing the direct evidence for the polymer chains grafting onto the exfoliated MMT. TEM investigation of the stretched nanocomposite film revealed that the microcracks in the nanocomposite film appeared mainly in the bulk region of polymer matrix, implying that the interfacial strength between P(MA‐co‐MMA) and its grafted MMT nanoplatelets was higher than the cohesion strength of P(MA‐co‐MMA). © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5891–5897, 2009     

Cu(0)/2,6‐bis(imino)pyridines catalyzed single‐electron transfer‐living radical polymerization of methyl methacrylate initiated with poly(vinylidene fluoride‐co‐chlorotrifluoroethylene)

A series of 2,6‐bis(imino)pyridines, as common ligands for late transition metal catalyst in ethylene coordination polymerization, were successfully employed in single‐electron transfer‐living radical polymerization (SET‐LRP) of methyl methacrylate (MMA) by using poly(vinylidene fluoride‐co‐chlorotrifluoroethylene) (P(VDF‐co‐CTFE)) as macroinitiator with low concentration of copper catalyst under relative mild‐reaction conditions. Well‐controlled polymerization features were observed under varied reaction conditions including reaction temperature, catalyst concentration, as well as monomer amount in feed. The typical side reactions including the chain‐transfer reaction and dehydrochlorination reaction happened on P(VDF‐co‐CTFE) in atom‐transfer radical polymerization process were avoided in current system. The relationship between the catalytic activity and the chemical structure of 2,6‐bis(imino)pyridine ligands was investigated by comparing both the electrochemical properties of Cu(II)/2,6‐bis(imino)pyridine and the kinetic results of SET‐LRP of MMA catalyzed with different ligands. The substitute groups onto N‐binding sites with proper steric bulk and electron donating are desirable for both high‐propagation reaction rate and C? Cl bonds activation capability on P(VDF‐co‐CTFE). The catalytic activity of Cu(0)/2,6‐bis(imino)pyridines is comparable with Cu(0)/2,2′‐bipyridine under the consistent reaction conditions. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4378–4388     

UV‐Absorbent Lignin‐Based Multi‐Arm Star Thermoplastic Elastomers

Lignin‐grafted copolymers, namely lignin‐graft‐poly(methyl methacrylate‐co‐butyl acrylate) (lignin‐g‐P(MMA‐co‐BA)), are synthesized via “grafting from” atom transfer radical polymerization (ATRP) with the aid of lignin‐based macroinitiators. By manipulating the monomer feed ratios of MMA/BA, grafted copolymers with tunable glass transition temperatures (−10–40 °C) are obtained. These copolymers are evaluated as sustainable thermoplastic elastomers (TPEs). The results suggest that the mechanical properties of these TPEs lignin‐g‐P(MMA‐co‐BA) copolymers are improved significantly by comparing with those of linear P(MMA‐co‐BA) copolymer counterparts, and the elastic strain recovery is nearly 70%. Lignin‐g‐P(MMA‐co‐BA) copolymers exhibit high absorption in the range of the UV spectrum, which might allow for applications in UV‐blocking coatings.

     

Blood cell separation using crosslinkable copolymers containing N,N‐dimethylacrylamide

Amphiphilic copolymers using hydrophilic N,N‐dimethylacrylamide (DMA), hydrophobic methyl methacrylate (MMA) and a crosslinkable monomer, 3‐methacryloyloxypropyl trimethoxysilane (MTSi), were synthesized and evaluated as coating materials for leukocyte removal filters for whole blood. When filters composed of non‐woven fabrics were coated with crosslinked synthesized copolymers, the elution ratios of the copolymers to water were adequately low because of the crosslinking with trimethoxysilane groups of MTSi units in the copolymers. Filters coated with crosslinked poly(DMA‐co‐MTSi) having a 0.96 mole fraction of DMA units showed a 0.35 ± 0.44% platelet permeation ratio and a logarithmic reduction of 4.0 ± 0.68 for leukocytes. On the other hand, an increase in the content of MMA units in the DMA‐containing copolymers improved the permeation ratio of the platelets dramatically. Filters coated with crosslinked poly(DMA‐co‐MMA‐co‐MTSi) containing a 0.39 mole fraction of MMA units and a 0.58 mole fraction of DMA units showed an 86 ± 3.0% platelet permeation ratio and a logarithmic reduction of 2.1 ± 1.2 for leukocytes. This indicates that an adequate content of hydrophobic monomer units, such as MMA units, is necessary for effective platelet permeation. Copyright © 2007 John Wiley & Sons, Ltd.     

Synthesis and characterization of amphiphilic heterograft copolymers with PAA and PS side chains via “Grafting from” approach

The amphiphilic heterograft copolymers poly(methyl methacrylate‐co‐2‐(2‐bromoisobutyryloxy)ethyl methacrylate)‐graft‐(poly(acrylic acid)/polystyrene) (P(MMA‐co‐BIEM)‐g‐(PAA/PS)) were synthesized successfully by the combination of single electron transfer‐living radical polymerization (SET‐LRP), single electron transfer‐nitroxide radical coupling (SET‐NRC), atom transfer radical polymerization (ATRP), and nitroxide‐mediated polymerization (NMP) via the “grafting from” approach. First, the linear polymer backbones poly(methyl methacrylate‐co‐2‐(2‐bromoisobutyryloxy)ethyl methacrylate) (P(MMA‐co‐BIEM)) were prepared by ATRP of methyl methacrylate (MMA) and 2‐hydroxyethyl methacrylate (HEMA) and subsequent esterification of the hydroxyl groups of the HEMA units with 2‐bromoisobutyryl bromide. Then the graft copolymers poly(methyl methacrylate‐co‐2‐(2‐bromoisobutyryloxy)ethyl methacrylate)‐graft‐poly(t‐butyl acrylate) (P(MMA‐co‐BIEM)‐g‐PtBA) were prepared by SET‐LRP of t‐butyl acrylate (tBA) at room temperature in the presence of 2,2,6,6‐tetramethylpiperidin‐1‐yloxyl (TEMPO), where the capping efficiency of TEMPO was so high that nearly every TEMPO trapped one polymer radicals formed by SET. Finally, the formed alkoxyamines via SET‐NRC in the main chain were used to initiate NMP of styrene and following selectively cleavage of t‐butyl esters of the PtBA side chains afforded the amphiphilic heterograft copolymers poly(methyl methacrylate‐co‐2‐(2‐bromoisobutyryloxy)ethyl methacrylate)‐graft‐(poly(t‐butyl acrylate)/polystyrene) (P(MMA‐co–BIEM)‐g‐(PtBA/PS)). The self‐assembly behaviors of the amphiphilic heterograft copolymers P(MMA‐co–BIEM)‐g‐(PAA/PS) in aqueous solution were investigated by AFM and DLS, and the results demonstrated that the morphologies of the formed micelles were dependent on the grafting density. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

A novel poly(p‐phenylene) containing alternating poly(perfluorooctylethyl acrylate‐co‐methyl methacrylate) and polystyrene grafts by combination of atom transfer radical polymerization and Suzuki coupling processes

A poly(p‐phenylene) (PP), carrying perfectly alternating, well‐defined poly(perfluorooctylethyl acrylate‐co‐methyl methacrylate) [P(FEA‐co‐MMA)] and polystyrene (PS) side chain grafts, was synthesized by the combination of atom transfer radical polymerization (ATRP) and Suzuki cross‐coupling processes. First, dibromobenzene and diboronic ester functional macromonomers of P(FEA‐co‐MMA) and PS, respectively, were prepared by ATRP. In the second step, PP with lateral alternating P(FEA‐co‐MMA) and PS chains was synthesized by a Suzuki coupling reaction in the presence of Pd(PPh₃)₄ catalyst. The wetting behavior of the polymers was studied by measurements of the static contact angle θ of thin films (200?400 nm thickness) using water and n‐hexadecane as wetting liquids. The obtained fluorinated PP showed high static contact angles with both interrogating liquids, exhibiting simultaneously hydrophobic (θ_w = 111°) and lipophobic (θ_h = 67°) properties. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Single‐chain nanoparticles with well‐defined structure via intramolecular crosslinking of linear polymers with pendant benzoxazine groups

Controlled intramolecular collapse of linear polymer chains with crosslinkable groups is an efficient way to prepare single‐chain nanoparticles in the size range of 5–20 nm. However, the nature of the crosslinking group is critical. In present study, poly(styrene‐co‐chloromethyl styrene) [P(St‐co‐CMS)] was synthesized via reversible addition‐fragmentation chain transfer (RAFT) polymerization and then was converted into polystyrene azide (PS? N₃). Polystyrene containing benzoxazine side groups [P(St‐co‐BS)], which can be used as the precusor for the later intramolecular collapse, was obtained from PS? N₃ and 3‐(4‐(prop‐2‐ynyloxy)phenyl)‐3,4‐dihydro‐2H‐benzo[e][1,3]oxazine (P‐APPE) via the method of click chemistry. The sub‐20 nm polymeric nanoparticles with well‐defined structure via thermally intramolecular crosslinking of P(St‐co‐BS) were prepared. The structure change from the linear polymers to the single‐chain nanoparticles was confirmed by nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR), and gel permeation chromatography (GPC). The morphology and the dimension of the nanoparticles were characterized by using transmission electron microscope (TEM), atomic force microscopy (AFM), as well as dynamic light scattering (DLS). The results reveal that the size of the nanoparticles can be regulated by changing the molecular weight of the precursors and the amount of pendant benzoxazine groups by the use of controlled polymerization techniques. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Synthesis of unsaturation containing P(VDF‐co‐TrFE‐co‐CTFE) from P(VDF‐co‐CTFE) in one‐pot catalyzed with Cu(0)‐based single electron transfer living radical polymerization system

Poly(vinylidene fluoride‐co‐trifluoroethylene‐co‐chlorotrifluoroethylene) (P(VDF‐co‐TrFE‐co‐CTFE)) with internal double bond has been reported with high dielectric constant and energy density at room temperature, which is expected to serve as a promising dielectric film in high pulse discharge capacitors. An environmentally friendly one‐pot route, including the controllable hydrogenation via Cu(0) mediated single electron transfer radical chain transfer reaction (SET‐CTR) and dehydrochlorination catalyzed with N‐containing reagent, is successfully developed to synthesize P(VDF‐co‐TrFE‐co‐CTFE) containing unsaturation. The resultant polymer was carefully characterized with ¹H NMR, ¹⁹F NMR, and FTIR. The composition of the resultant copolymer is strongly influenced by reaction conditions, including the reaction temperature, catalyst concentration, the types of ligands and solvents. The kinetics data of the chain transfer and elimination reaction demonstrate their well‐controlled feature of the strategy. By shifting the equilibrium between the CTR and elimination reactions dominated by N‐compounds serving as ligands in SET‐CTR and catalyst in the dehydrochlorination of P(VDF‐co‐CTFE), P(VDF‐co‐TrFE‐co‐CTFE) with tunable TrFE and double‐bond content could be synthesized in this one‐pot route. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 3429–3440     

Construction of temperature responsive hybrid crosslinked self‐assemblies based on PEG‐b‐P(MMA‐co‐MPMA)‐b‐PNIPAAm triblock copolymer: ATRP synthesis and thermoinduced association behavior

A novel amphiphilic thermosensitive poly(ethylene glycol)₄₅‐b‐poly(methyl methacrylate₄₆‐co‐3‐(trimethoxysilyl)propyl methacrylate)₂‐b‐poly(N‐isopropylacrylamide)₄₂₉ (PEG₄₅‐b‐P(MMA₄₆‐co‐MPMA₂)‐b‐PNIPAAm₄₂₉) triblock copolymer was synthesized via consecutive atom transfer radical polymerization techniques. The thermoinduced association behavior of the resulting triblock copolymers in aqueous medium was further investigated in detail by ¹H NMR, transmission electron microscopy, and dynamic light scattering. The results showed that at the temperature (25 °C) below the LCST, PEG₄₅‐b‐P(MMA₄₆‐co‐MPMA₂)‐b‐PNIPAAm₄₂₉ triblock copolymers self‐assembled into the core crosslinked micelles with the hydrophobic P(MMA‐co‐MPMA) block constructing a dense core, protected by the mixed soluble PEG and PNIPAAm chains acting as a hydrophilic shell simultaneously. With an increase in temperature, the resulting core‐shell micelles converted into a new type of micelles with the hydrophilic PEG chains stretching out from the hydrophobic core through the collapsed PNIPAAm shell. On the other hand, at the temperature (40 °C) above the LCST, such triblock copolymers formed the crosslinked vesicles with the hydrophobic PNIPAAm and P(MMA‐co‐MPMA) blocks constructing a membrane core and the soluble PEG chains building the hydrophilic lumen and the shell. On further decreasing the temperature, the resulting vesicles underwent transformation from the shrunken to the expanded status, leading to the formation of swollen vesicles with enlarged size. This study is believed to present the first formation of two types of hybrid crosslinked self‐assemblies by thermoinduced regulation. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Free‐radical crosslinking copolymerization of 2,2′‐azobis[N‐(2‐propenyl)‐2‐methylpropionamide] with vinyl benzoate resulting in polymeric azo initiators

2,2′‐Azobis[N‐(2‐propenyl)‐2‐methylpropionamide] (APMPA) with two carbon–carbon double bonds and an azo group was copolymerized with vinyl benzoate (VBz) at 60 °C, resulting in azo groups containing VBz/APMPA prepolymers and crosslinked polymers as soluble and insoluble polymeric azo initiators, respectively. The polymerization characteristics of APMPA as a novel diallyl monomer were clarified with the rate and degree of polymerization and the monomer reactivity ratios. The gelation behaviors in VBz/APMPA crosslinking copolymerizations were examined in detail with a comparison of the actual gel point and the theoretical gel point calculated according to Stockmayer's equation with the tentative assumption of equal reactivity for both vinyl groups belonging to VBz and APMPA. The effectiveness of the resulting branched or crosslinked poly(VBz‐co‐APMPA)s as soluble or insoluble polymeric azo initiators, respectively, at providing graft polymers through the cleavage of azo groups at an elevated temperature was examined by the polymerization of allyl benzoate at 120 °C. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 317–325, 2002