Light‐triggered reversible solubility of α‐cyclodextrin and azobenzene moiety complexes in PDMAA‐co‐PAPA via molecular recognition

Photoresponsive polymer with azobenzene pendant group (PDMAA‐co‐PAPA) was synthesized by radical polymerization of N,N‐dimethylacrylamide (DMAA) and N‐4‐phenylazophenyl acrylamide (PAPA), and the characterization of the inclusion complexes of the PDMAA‐co‐PAPA with α‐cyclodextrin (α‐CD) were performed by FTIR, GPC, ¹H NMR, 2D NOESY, and UV–vis spectroscopy. It was found that the solubility of PDMAA‐co‐PAPA and α‐CD inclusion complexes in aqueous solution showed tunable property, which could be triggered by alternating UV–vis light irradiation at a certain temperature due to the effect of molecular recognition of α‐CD with azobenzene moiety in the polymer. After UV irradiation, the lower critical solution temperature (LCST) of the polymer aqueous solution increased slightly without α‐CD while the LCST decreased sharply at presence of α‐CD. Furthermore, UV spectroscopy showed that the photoisomerization of the polymer solution went on rapidly and reversibly, and 2D NOESY data suggested that the inclusion complexation of α‐CD with trans azobenzene moiety and the decomplexation with cis azobenzene resulted in reversible solubility behavior when objected to UV and Vis light irradiation alternately. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and characterization of poly(thiophen‐3‐yl acetic acid 4‐pyrrol‐1‐yl phenyl ester‐co‐N‐methylpyrrole) and its application in an electrochromic device

Copolymer of thiophen‐3‐yl acetic acid 4‐pyrrol‐1‐yl phenyl ester (TAPE) with N‐methylpyrrole (NMPy) was synthesized by potentiostatic electrochemical polymerization in acetonitrile–tetrabutylammonium tetrafluoroborate solvent–electrolyte couple. The chemical structures were confirmed via Fourier transform infrared spectroscopy (FTIR), cyclic voltammetry (CV), and UV–vis spectroscopy. Electrochromic and spectroelectrochemical properties of poly(TAPE‐co‐NMPy) [P(TAPE‐co‐NMPy)] were investigated. Results showed that the copolymer revealed color change between light yellow and green upon doping and dedoping of the copolymer, with a moderate switching time. Furthermore, as an application, dual‐type absorptive/transmissive polymer electrochromic device (ECD) based on poly(TAPE‐co‐NMPy) and poly(3,4‐ethylene dioxythiophene) (PEDOT) have been assembled, where spectroelectrochemistry, switching ability, stability, and optical memory of the ECD were investigated. Results showed that the device exhibited good optical memory and stability with moderate switching time. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1988–1994, 2006     

Comparison of poly(o‐anisidine) and poly(o‐anisidine‐co‐aniline) copolymer synthesized by chemical oxidative method

In this study, poly(o‐anisidine) [POA], poly(o‐anisidine‐co‐aniline) [POA‐co‐A], and polyaniline [PANi] were chemically synthesized using a single polymerization process with aniline and o‐anisidine as the respective monomers. During the polymerization process, p‐toluene sulfonic acid monohydrate was used as a dopant while ammonium persulfate was used as an oxidant. N‐methyl‐pyrolidone (NMP) was used as a solvent. We observed that the ATR spectra of POA‐co‐A showed features similar to those of PANi and POA as well as additional ones. POA‐co‐A also achieved broader and more extended UV–vis absorption than POA but less than PANi. The chemical and electronic structure of the product of polymerization was studied using Attenuated Total Reflectance spectroscopy (ATR) and UV–visible spectroscopy (UV–vis). The transition temperature of the homopolymers and copolymers was studied using differential scanning calorimetry and the viscosity average molecular weight was studied by using dilute solution viscometry. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis and characterization of a copolymer: Poly(aniline‐co‐fluoroaniline)

In the present article, we report the chemical synthesis and characterization of poly(aniline‐co‐fluoroaniline) [poly(An‐FAn)]. The copolymerization of aniline and 2‐fluoroaniline was carried out by chemical method in acidic medium. The characterization of poly(aniline‐co‐fluoroaniline) was done using FTIR, UV‐visible spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron micrography (SEM), and a four‐points‐probe conductivity method. X‐ray diffraction (XRD) and SEM characterization reveal crystalline nature of doped copolymer compared to undoped copolymer. The observed decrease in the conductivity of the copolymer relative to polyaniline is attributed to the incorporation of the fluoro moieties into the polyaniline chain. The chemically synthesized copolymer shows good solubility in common organic solvents, and is, therefore, technological useful. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1460–1466, 2001     

ZnO nanoparticles dispersed poly(aniline‐co‐o‐anthranilic acid) composites: Photocatalytic reduction of Cr(VI) and Ni(II)

In this report, poly(aniline‐co‐anthranilic acid)/zinc oxide (poly(ANI‐co‐ANA)/ZnO) nanocomposites were prepared by in‐situ chemical oxidative polymerization. Transmission electron microscopy (TEM), X‐ray diffraction, Fourier transform infrared spectroscopy, and ultraviolet–visible spectroscopy measurements were used to characterize the resulting pure copolymer and nanocomposite. TEM analysis showed that the nanoparticles with a mean diameter of 15–25 nm were dispersed in the copolymer matrix. Thermogravimetric analysis indicated that the nanocomposite had a higher decomposition temperature than the pure copolymer. The conductivity measurements showed the resulting nanocomposite possessed higher conductivity as compared to the pure copolymer. Photocatalytic removal of Cr(VI) and Ni(II) from aqueous solution using as‐synthesized nanocomposite under UV‐light irradiation was studied. The reduction patterns of Cr(VI) and Ni(II) were better fitted to first‐order kinetic model. The nanocomposite was also applied as a photocatalyst for the degradation of methylene blue dye. The result revealed substantial degradation of the dye (∼82%) under UV‐light illumination. POLYM. COMPOS., 35:839–846, 2014. © 2013 Society of Plastics Engineers     

Synthesis and characterization of conducting copolymer of Trans‐1‐(4‐methyl‐3′‐thienyl)‐2‐(ferrocenyl)ethene with EDOT

Ferrocene‐substituted conducting polymer namely poly(trans‐1‐(4‐methyl‐3′‐thienyl)‐2‐(ferrocenyl)ethene‐co‐3,4‐ethylenedioxythiophene) [P(MTFE‐co‐EDOT)] was synthesized and its electrochromic properties were studied. Monomer, MTFE, was obtained using 2‐(ferrocenyl)ethene and 3‐methyl‐4‐bromothiophene. The structure of monomer was determined via Fourier transform infrared spectroscopy (FTIR), ¹H‐NMR, and ¹³C‐NMR techniques. The copolymer was synthesized using this monomer and EDOT. The resulting copolymer P(MTFE‐co‐EDOT) was characterized by cyclic voltammetry, FTIR, scanning electron microscopy, atomic force microscopy, and UV–vis spectroscopy. The conductivity measurements of copolymer and PEDOT were accomplished by the four‐probe technique. Although poly(trans‐1‐(4‐methyl‐3′‐thienyl)‐2‐(ferrocenyl)ethene) [P(MTFE)] reveals no electrochromic activity, its copolymer with EDOT has two different colors (violet and gray). Band gap (E_g) and λ_max of P(MTFE‐co‐EDOT) were determined. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Electrochemical preparation of poly(2‐bromoaniline) and poly(aniline‐co‐2‐bromoaniline) in acetonitrile

Electrochemical preparation of poly(2‐bromoaniline) (PBrANI) and poly(aniline‐co‐2‐bromoaniline) [P(An‐co‐2‐BrAn)] was carried out in an acetonitrile solution containing tetrabutylammonium perchlorate (TBAP) and perchloric acid (HClO₄). The cyclic voltammograms during the copolymerization had many features similar to those for the usual polymerization of aniline. The copolymer exhibits a higher dry electrical conductivity value than that of PBrANI and a lower one than that of PANI. The observed decrease in the conductivity of the copolymer relative to PANI is attributed to the incorporation of bromine moieties into the polyaniline chain. The structure and properties of the polymer and copolymer were elucidated using cyclic voltammetry (CV), FTIR, and UV‐vis spectroscopy. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2460–2468, 2003     

Simultaneous lower and upper critical solution temperature‐type co‐nonsolvency behaviour exhibited in water–dioxane mixtures by linear copolymers and hydrogels containing N‐isopropylacrylamide and N,N‐dimethylacrylamide

The co‐nonsolvency behaviour in water–dioxane mixtures of linear copolymers and hydrogels consisting of N‐isopropylacrylamide (NIPAM) and N,N‐dimethylacrylamide (DMAM) was studied as a function of solvent composition and temperature. The composition of the copolymers, P(NIPAM‐co‐DMAMx), in DMAM units, x, varies from x = 0 up to x = 100%. It is shown that the copolymers combine the lower critical solution temperature (LCST)‐type co‐nonsolvency behaviour of poly‐NIPAM with the upper critical solution temperature (UCST)‐type co‐nonsolvency behaviour of poly‐DMAM. Depending on x, both the LCST‐ and UCST‐type co‐nonsolvency behaviour may be simultaneously observed in water‐rich and dioxane‐rich solvent mixtures, respectively. Due to this complex phase separation behaviour, the variation of the reduced viscosity of the linear copolymers, as well as the swelling–deswelling behaviour of the respective hydrogels, are shown to be temperature‐ and solvent‐sensitive. Copyright © 2006 Society of Chemical Industry     

Preparation and characterization of polystyrene/titanium dioxide composite particles containing organic ultraviolet‐stabilizer groups

Polystyrene/titanium dioxide (TiO₂) composite particles containing organic ultraviolet (UV)‐stabilizer groups were prepared by the emulsion copolymerization of styrene and 2‐hydroxy‐4‐(3‐methacryloxy‐2‐hydroxylpropoxy)benzophenone with sodium sulfopropyl lauryl maleate as a surfactant in the presence of rutile TiO₂ modified with 3‐(trimethoxysilyl) propyl methacrylate, and the product was poly[styrene‐co‐sodium sulfopropyl lauryl maleate‐co‐2‐hydroxy‐4‐(3‐methacryloxy‐2‐hydroxylpropoxy) benzophenone] [poly(St‐co‐M12‐co‐BPMA)]/TiO₂ composite particles. The structures of the composite particles were characterized with Fourier transform infrared spectroscopy, ultraviolet–visible (UV–vis) absorption spectroscopy, thermogravimetric analysis, and differential scanning calorimetry. The Fourier transform infrared and UV–vis measurements showed that poly(St‐co‐M12‐co‐BPMA) was grafted from the surface of TiO₂, and this copolymer possessed a high absorbance capacity for UV light, which is very important for improving the UV resistance of polystyrene. The thermogravimetric analysis measurements indicated that the percentage of grafting and the grafting efficiency could reach 513.9 and 59.9%, respectively. The differential scanning calorimetry measurement indicated that the glass‐transition temperature of the poly(St‐co‐M12‐co‐BPMA)/TiO₂ composite particles was higher than that of poly (St‐co‐M12‐co‐BPMA).These research results are very important for preparing polystyrene with high UV resistance. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Electrochromic properties and electrochromic device application of copolymer of N‐(4‐(3‐thienyl methylene)‐oxycarbonylphenyl)maleimide with thiophene

A new copolymer of N‐(4‐(3‐thienyl methylene)‐oxycarbonylphenyl)maleimide (MBThi) with thiophene [P(MBThi‐co‐Th)] was synthesized electrochemically in the presence of tetrabutylammonium tetrafluoroborate as the supporting electrolyte, in acetonitrile/borontrifluoride ethylether solvent mixture (80 : 20, v/v). Spectroelectrochemical analysis of the resulting copolymer reflected electronic transitions at 440, 730, and ～1000 nm, revealing π–π* transition, polaron, and bipolaron band formation, respectively. Switching ability was evaluated by a kinetic study via measuring the transmittance (%T) at the maximum contrast. Dual‐type polymer electrochromic devices (ECDs) based on P(MBThi‐co‐Th) and poly(ethylene dioxythiophene) (PEDOT) were constructed. Spectroelectrochemistry, switching ability, and stability of the devices were investigated by UV–vis spectroscopy and cyclic voltammetry. These devices exhibit low switching voltages (between 0.0 and +2.0 V) and short switching times with reasonable switching stability under atmospheric conditions. © 2006 Wiley Periodicals, Inc. J Appl PolymSci 102: 4500–4505, 2006     

Photografted polymeric networks based on N‐isopropylacrylamide: Depth profiling by infrared spectroscopy

The study presents the application of infrared spectroscopy in attenuated reflection geometry with variable angle of incidence (VA‐ATR‐FTIR) in analysis of the in‐depth distribution of several chemical species in photografted layers. Two types of networks based on N‐isopropylacrylamide (NIPA) and one interpenetrated network of NIPA and N,N‐dimethylacrylamide (DMA) were produced by UV‐induced graft polymerization on polypropylene surfaces. The NIPA‐g‐PP samples were obtained in two different UV irradiation conditions: under broad band irradiation and using soft UV light (λ > 300 nm). NIPA‐co‐DMA‐g‐PP has been obtained using λ > 300 nm. VA‐ATR‐FTIR spectroscopy revealed the distribution of NIPA and DMA units across the thickness of the probed layer, according to the network type and photografting conditions. The spectral analysis of NIPA‐g‐PP reveals the influence of irradiation conditions, particularly the UV‐B radiation, on the coupling of monomers. For the NIPA‐co‐DMA‐g‐PP sample, a slight agglomeration of DMA units near the surface has been observed, which is maybe related to the more reactive character of DMA. According to the nonhomogenous distribution of the NIPA and DMA units inside the grafted layer, the surface contribution can be separated from the bulk one. The depth profile of several chemical species has been finally constructed. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46048.     

Synthesis,characterization, and antimicrobial activity of silver nanoparticles on poly(GMA‐co‐EGDMA) polymer support

Poly(glycidyl methacrylate‐co‐ethylene glycol dimethacrylate) (poly(GMA‐co‐EGDMA) macroporous copolymer decorated with silver nanoparticles was prepared by a modification of poly(GMA‐co‐EGDMA) in the reaction with arginine, and consequent reduction of silver ions with amino groups. The mercury intrusion porosimetry, transmission electron microscopy, X‐ray diffraction, UV–vis reflection spectroscopy, and inductively coupled plasma atomic emission measurements were used to characterize obtained composite. The coordination of silver nanoparticles to the poly(GMA‐co‐EGDMA) copolymer was studied using infrared spectroscopy. Time dependence and concentration dependence of the antimicrobial efficiency of composite were tested against Gram‐negative bacteria Escherichia coli , Gram‐positive bacteria Staphylococcus aureus , and fungus Candida albicans . The composite ensured maximum reduction of both bacteria, while the fungi reduction reached satisfactory 96.8%. Preliminary antimicrobial efficiency measurements using laboratory flow setup indicated potential applicability of composite for wastewater treatment. POLYM. COMPOS., 38:1206–1214, 2017. © 2015 Society of Plastics Engineers     

Influence of ethyl methacrylate content on the volume‐phase transition of temperature‐sensitive poly[(N‐isopropylacrylamide)‐co‐(ethyl methacrylate)] microgels

A novel series of temperature‐sensitive poly[(N‐isopropylacrylamide)‐co‐(ethyl methacrylate)] (p(NIPAM‐co‐EMA)) microgels was prepared by the surfactant‐free radical polymerization of N‐isopropylacrylamide (NIPAM) with ethyl methacrylate (EMA). The shape, size dispersity and volume‐phase transition behavior of the microgels were investigated by transmission electron microscopy (TEM), ultraviolet–visible (UV–Vis) spectroscopy, dynamic light scattering (DLS) and differential scanning calorimetry (DSC). The transmission electron micrographs and DLS results showed that microgels with narrow distributions were prepared. It was shown from UV–Vis, DLS and DSC measurements that the volume‐phase transition temperature (VPTT) of the p(NIPAM‐co‐EMA) microgels decreased with increasing incorporation of EMA, but the temperature‐sensitivity was impaired when more EMA was incorporated, causing the volume‐phase transition of the microgels to become more continuous. It is noteworthy that incorporation of moderate amounts of EMA could not only lower the VPTT but also enhance the temperature‐sensitivity of the microgels. The reason for this phenomenon could be attributed to changes in the complicated interactions between the various molecules. Copyright © 2004 Society of Chemical Industry     

Drug release from electrospun fibers of poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) grafted with poly(N‐vinylpyrrolidone)

Poly(N‐vinylpyrrolidone) (PVP) groups were grafted onto poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV) backbone to modify the properties of PHBV and synthesize a new novel biocompatible graft copolymer. Based on these graft copolymers, electrospun fiber mats and commonly cast films were explored as drug delivery vehicles using tetracycline hydrochloride as a model drug. Toward that end, the fibers were electrospun and the films were cast from chloroform solutions containing a small amount of methanol to solubilize the drug. The Brookfield viscosities of the solution were determined to achieve the optimal electrospinning conditions. The vitro release of the tetracycline hydrochloride from these new drug delivery systems was followed by UV–vis spectroscopy. To probe into the factors affected on the release behavior of these drug delivery systems, their water absorbing abilities in phosphate buffer solution were investigated, together with their surface hydrophilicity, porosity and crystallization properties were characterized by water contact angles, capillary flow porometer, DSC, and WAXD, respectively. The morphological changes of these drug delivery vehicles before and after release were also observed with SEM. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis and characterization of a ferrocene‐modified,polyaniline‐like conducting polymer

A novel monomer called 1,1′‐ferrocenediacyl anilide (FcA) was synthesized from ferrocene (Fc). Copolymerization was carried out between FcA and aniline (ANI) by an electrochemical method. The novel monomer and copolymer were characterized with ¹H‐NMR, Fourier transform infrared (FTIR) spectroscopy, and ultraviolet–visible (UV–vis) spectroscopy. The hydrogen protons of the benzene ring were moved to a low field in ¹H‐NMR, and the absorption band of N?Q?N (where Q is the quinoid ring) appeared in the FTIR spectrum of the polymer. The peaks of both Fc and the π–π* electronic transition in the UV–vis spectra were redshifted. The results indicate that the copolymer mainly existed as a highly delocalized conjugated system. X‐ray diffraction analysis established further proof, and the process of electrochemical deposition was observed by scanning electron microscopy. The optimal synthesis conditions of the copolymer were determined through changes in the monomer molar ratios and the scan rate. The ideal performance of the copolymer was gained when the monomer molar ratio between FcA and ANI was 1:4 and the scan rate was 50 mV/s. Furthermore, the electrochemical performances were tested in detail by cyclic voltammetry, galvanostatic charge–discharge testing, and electrochemical impedance spectroscopy. The results show that the specific capacitance of poly(1,1′‐ferrocenediacyl anilide‐co‐aniline) increased up to 433.1 F/g at 0.5 A/g, the diffusion resistance was very small, and the durability was good enough. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43217.     

Towards enhanced electrochemical capacitance with self‐assembled synthesis of poly(pyrrole‐co‐o‐toluidine) nanoparticles

Poly(pyrrole‐co‐o‐toluidine) (PPOT) nanoparticles for electrochemical capacitors are easily and productively synthesized by a chemical oxidative polymerization of pyrrole (PY) and o‐toluidine (OT) in 0.5M HCl without any external additive. The polymerization yield, electrical conductivity, and size of the copolymer nanoparticles can significantly be optimized by the oxidant/monomer molar ratio and polymerization temperature. The chemical structure of the obtained copolymer is characterized by UV–vis and FTIR. The copolymer nanoparticles synthesized at 10°C are found to generally have irregular granular morphology with a diameter of 60–100 nm and a small polydispersity index of 1.06 by laser particle‐size analyzer, FE‐SEM, and TEM, and good dispersibility in water. The formation mechanism of the nanoparticles is proposed based on the powerful amphipathicity from comonomer aggregate formed by PY and OT in the monomer solution. The PPOT nanoparticles possess a specific capacitance of 310 F g^?1 at 25 mV s^?1 as well as retain 81% of the initial specific capacitance value after 1000 cycles, while its energy density and power density are found to be 40.2 and 1196 W Kg^?1 at 2 A g^?1. The enhanced electrochemical properties can be attributed to the nanostructural advantage of the PPOT. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42995.     

Synthesis and characterization of N‐ and O‐alkylated poly[aniline‐co‐N‐(2‐hydroxyethyl) aniline]

Poly[aniline‐co‐N‐(2‐hydroxyethyl) aniline] was synthesized in an aqueous hydrochloric acid medium with a determined feed ratio by chemical oxidative polymerization. This polymer was used as a functional conducting polymer intermediate because of its side‐group reactivity. To synthesize the alkyl‐substituted copolymer, the initial copolymer was reacted with NaH to obtain the N‐ and O‐anionic copolymer after the reaction with octadecyl bromide to prepare the octadecyl‐substituted polymer. The microstructure of the obtained polymers was characterized by Fourier transform infrared spectroscopy, ¹H‐NMR, and X‐ray diffraction. The thermal behavior of the polymers was investigated by thermogravimetric analysis and differential scanning calorimetry. The morphology of obtained copolymers was studied by scanning electron microscopy. The cyclic voltammetry investigation showed the electroactivity of poly [aniline‐co‐N‐(2‐hydroxyethyl) aniline] and N and O‐alkylated poly[aniline‐co‐N‐(2‐hydroxyethyl) aniline]. The conductivities of the polymers were 5 × 10^?5 S/cm for poly[aniline‐co‐N‐(2‐hydroxyethyl) aniline] and 5 ×10^?7 S/cm for the octadecyl‐substituted copolymer. The conductivity measurements were performed with a four‐point probe method. The solubility of the initial copolymer in common organic solvents such as N‐methyl‐2‐pyrrolidone and dimethylformamide was greater than polyaniline. The alkylated copolymer was mainly soluble in nonpolar solvents such as n‐hexane and cyclohexane. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Thermosensitive phase transition kinetics of poly(N‐isopropylacryl amide‐co‐acrylamide) microgel aqueous dispersions

Thermosensitive poly(N‐isopropylacrylamide‐co‐acrylamide) microgel particles were prepared through precipitation polymerization. The diameters of the microgel particles were in the range of 220–270 nm and showed a monodispersion. The lower critical solution temperatures (LCST) of the microgel dispersions were measured by dynamic light scattering and turbidimetric analysis. The results indicated that the LCST increased with an increase of acrylamide (AAm) content in the copolymer composition. The kinetics of the thermosensitive phase transitions of the microgel particles were investigated by time‐course UV–vis spectroscopy. The results indicated that the higher the content of AAm in copolymer composition, the more time is required for equilibrium deswelling and the less time required for equilibrium swelling. In addition, the time required for equilibrium deswelling decreased with an increase of the content of the microgel particles in dispersions. By contrast, the time required for equilibrium swelling increased slightly. Thus, a suitable LCST and time required for equilibrium of phase transition can be achieved by adjusting the molar ratio of the comonomers in the microgels and the content of the microgel particles in dispersions. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation and electrochemical capacitance of poly(pyrrole‐co‐aniline)

The copolymer of pyrrole and aniline, poly(pyrrole‐co‐aniline), has been prepared by chemical oxidation of corresponding monomer mixtures with ammonium peroxysulfate. Techniques of FTIR, SEM‐EDS, and BET surface area measurement were used to characterize the structure and morphology of the copolymer. The electrochemical properties of the copolymer were investigated by cyclic voltammetry, galvanostatic charge‐discharge, and electrochemical impedance spectroscopy. The results indicated that poly(pyrrole‐co‐aniline) was about 100–300 nm in diameter and showed better electrochemical capacitive performance than polypyrrole and polyaniline. The specific capacitance of the copolymer electrode was 827 F/g at a current of 8 mA/cm² in 1 mol/L Na₂SO₄ electrolyte. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Poly(N‐isopropylacrylamide‐co‐hydroxyethyl methacrylate) graft copolymers and their application as carriers for drug delivery system

Poly(N‐isopropylacrylamide‐co‐hydroxyethyl methacrylate) [P(NIPAM‐co‐HEMA)] copolymer was synthesized by controlled radical polymerization from respective N‐isopropylacrylamide (NIPAM) and hydroxyethyl methacrylate (HEMA) monomers with a predetermined ratio. To prepare the thermosensitive and biodegradable nanoparticles, new thermosensitive graft copolymer, poly(L ‐lactide)‐graft‐poly(N‐isoporylacrylamide‐co‐hydroxyethyl methacrylate) [PLLA‐g‐P(NIPAM‐co‐HEMA)], with the lower critical solution temperature (LCST) near the normal body temperature, was synthesized by ring opening polymerization of L ‐lactide in the presence of P(NIPAM‐co‐HEMA). The amphiphilic property of the graft copolymers was formed by the grafting of the PLLA hydrophobic chains onto the PNIPAM based hydrophilic backbone. Therefore, the graft copolymers can self‐assemble into uniformly spherical micelles ò about 150–240 nm in diameter as observed by the field emission scanning electron microscope and dynamic light scattering. Dexamethasone can be loaded into these nanostructures during dialysis with a relative high loading capacity and its in vitro release depends on temperature. Above the LCST, most of the drugs were released from the drug‐loaded micelles, whereas a large amount of drugs still remains in the micelles after 48 h below the LCST. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012