共查询到20条相似文献,搜索用时 15 毫秒
1.
Yanfeng Zhang Hao Liu Jinming Hu Changhua Li Shiyong Liu 《Macromolecular rapid communications》2009,30(11):941-947
We report the first example of the synthesis and the “schizophrenic” micellization behavior of a multi‐responsive double hydrophilic ABC miktoarm star terpolymer. A well‐defined miktoarm star terpolymer consisting of poly(ethylene glycol), poly(2‐(diethylamino)ethyl methacrylate), and poly(N‐isopropylacrylamide) arms, PEG(‐b‐PDEA)‐b‐PNIPAM, was synthesized via the combination of atom transfer radical polymerization (ATRP) and click reaction. Containing pH‐responsive PDEA and thermo‐responsive PNIPAM arms, this novel type of miktoarm star terpolymer molecularly dissolves in aqueous solution at acidic pH and room temperature, but supramolecularly self‐assembles into PDEA‐core micelles at alkaline pH and room temperature, and PNIPAM‐core micelles at acidic pH and elevated temperatures. Most importantly, both types of micellar aggregates possess well‐solvated hybrid coronas.
2.
Lei Li Xiao‐Wei Kan Xin‐Xing Deng Cheng‐Cheng Song Fu‐Sheng Du Zi‐Chen Li 《Journal of polymer science. Part A, Polymer chemistry》2013,51(4):865-873
In this article, we demonstrate the Passerini three‐component reaction as a simple, effective method for the synthesis of polymers with double functional end groups, which are key precursors for the preparation of ABC miktoarm terpolymers. Thus, via the one‐step Passerini reaction of monomethoxy poly(ethylene glycol)–propionaldehyde (PEG‐CHO) with 2‐bromo‐2‐methylpropionic acid and propargyl isocyanoacetamide, the PEG chain end was simultaneously functionalized with one atom transfer radical polymerization (ATRP) initiating site and one alkynyl group. The resulting PEG(‐alkynyl)‐Br was then used for the synthesis of three types of miktoarm ABC terpolymers via two approaches. First, we conducted ATRP of N‐isopropylacrylamide (NIPAM), then click reaction with azido‐terminated polystyrene (PS‐N3) or poly(tert‐butyl acrylate) (PtBA‐N3) and obtained two ABC miktoarm terpolymers PEG(‐b‐PNIPAM)‐b‐PS and PEG(‐b‐PNIPAM)‐b‐PtBA. Alternatively, we conducted single electron transfer living radical polymerization of tBA and click reaction with PS‐N3 simultaneously to give PEG(‐b‐PtBA)‐b‐PS. All the polymer precursors and miktoarm terpolymers have been characterized by 1H NMR, Fourier transform infrared, gel permeation chromatography, demonstrating that both approaches provided well‐defined ABC miktoarm terpolymers. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 相似文献
3.
Yanfeng Zhang Hao Liu Hefei Dong Changhua Li Shiyong Liu 《Journal of polymer science. Part A, Polymer chemistry》2009,47(6):1636-1650
Amphiphilic ABC miktoarm star terpolymers consisting of polystyrene, poly(ε‐caprolactone), and poly(N‐isopropylacrylamide) arms, PS(‐b‐PNIPAM)‐b‐PCL, were synthesized via a combination of atom transfer radical polymerization, ring‐opening polymerization (ROP), and click chemistry. Difunctional PS bearing an alkynyl and a primary hydroxyl moiety at the chain end, PS‐alknyl‐OH, was prepared by reacting azido‐terminated PS with an excess of 3,5‐bis(propargyloxy)benzyl alcohol (BPBA) under click conditions. The subsequent ROP of ε‐caprolactone using PS‐alknyl‐OH macroinitiator afforded PS(‐alkynyl)‐b‐PCL copolymer bearing an alkynyl moiety at the diblock junction point. Target PS(‐b‐PNIPAM)‐b‐PCL amphiphilic ABC miktoarm star terpolymers were then prepared via click reaction between PS(‐alkynyl)‐b‐PCL and an excess of azido‐terminated PNIPAM (PNIPAM‐N3). The removal of excess PNIPAM‐N3 was accomplished by “clicking” onto alkynyl‐functionalized Wang resin. All the intermediate and final products were characterized by gel permeation chromatography, 1H NMR, and FTIR. In aqueous solution, the obtained amphiphilic ABC miktoarm star terpolymer self‐assembles into micelles possessing mixed PS/PCL cores and thermoresponsive shells, which were further characterized by dynamic laser light scattering and transmission electron microscopy. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1636–1650, 2009 相似文献
4.
Ikhlas Gadwal Prakash P. Wadgaonkar Amol B. Ichake Shivshankar R. Mane 《Journal of polymer science. Part A, Polymer chemistry》2019,57(2):146-156
A new approach was developed for synthesis of certain A3B3‐type of double hydrophilic or amphiphilic miktoarm star polymers using a combination of “grafting onto” and “grafting from” methods. To achieve the synthesis of desired miktoarm star polymers, acetyl protected poly(ethylene glycol) (PEG) thiols (Mn = 550 and 2000 g mol?1) were utilized to generate A3‐type of homoarm star polymers through an in situ protective group removal and a subsequent thiol–epoxy “click” reaction with a tris‐epoxide core viz. 1,1,1‐tris(4‐hydroxyphenyl)ethane triglycidyl ether. The secondary hydroxyl groups generated adjacent to the core upon the thiol–epoxy reaction were esterified with α‐bromoisobutyryl bromide to install atom transfer radical polymerization (ATRP) initiating sites. ATRP of N‐isopropylacrylamide (NIPAM) using the three‐arm star PEG polymer fitted with ATRP initiating sites adjacent to the core afforded A3B3‐type of double hydrophilic (PEG)3[poly(N‐isopropylacrylamide)] (PNIPAM)3 miktoarm star polymers. Furthermore, the generated hydroxyl groups were directly used as initiator for ring‐opening polymerization of ε‐caprolactone to prepare A3B3‐type of amphiphilic (PEG)3[poly(ε‐caprolactone)]3 miktoarm star polymers. The double hydrophilic (PEG)3(PNIPAM)3 miktoarm star polymers showed lower critical solution temperature around 34 °C. The preliminary transmission electron microscopy analysis indicated formation of self‐assembly of (PEG)3(PNIPAM)3 miktoarm star polymer in aqueous solution. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 146–156 相似文献
5.
Hakan Durmaz Figen Karatas Umit Tunca Gurkan Hizal 《Journal of polymer science. Part A, Polymer chemistry》2006,44(1):499-509
The ABC type miktoarm star terpolymer was prepared utilizing “core‐in” and “core‐out” methods via combination of Diels–Alder reaction (DA), stable free radical polymerization (SFRP), and atom transfer radical polymerization (ATRP). First, in DA reaction, poly(ethylene glycol)‐maleimide (PEG‐maleimide) precursor was reacted with succinic acid anthracen‐9‐ylmethyl ester 3‐(2‐bromo‐2‐methyl‐propionyloxy)‐2‐methyl‐2‐[2‐phenyl‐2‐(2,2,6,6‐tetramethyl‐piperidin‐1‐yloxy)‐ethoxy‐carbonyl]‐propyl ester, 8 , to give DA adduct, 9 , which has appropriate functional groups for SFRP and ATRP. Second, a previously obtained 9 was used as a macroinitiator for SFRP of styrene at 125 °C. As a third step, this PEG‐polystyrene (PEG‐PSt) precursor with a bromine functionality in the core was employed as a macroinitiator for ATRP of tert‐butylacrylate (tBA) in the presence of Cu(I)Br and pentamethyldiethylenetriamine at 80 °C to give ABC type miktoarm star terpolymer (PEG‐PSt‐PtBA) with controlled molecular weight and low polydispersity (Mw/Mn < 1.27). The obtained polymers were characterized by gel permeation chromatography and 1H NMR. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 499–509, 2006 相似文献
6.
Cigdem Celik Gurkan Hizal Umit Tunca 《Journal of polymer science. Part A, Polymer chemistry》2003,41(16):2542-2548
A trifunctional initiator, 2‐phenyl‐2‐[(2,2,6,6‐tetramethyl)‐1‐piperidinyloxy] ethyl 2,2‐bis[methyl(2‐bromopropionato)] propionate, was synthesized and used for the synthesis of miktoarm star AB2 and miktoarm star block AB2C2 copolymers via a combination of stable free‐radical polymerization (SFRP) and atom transfer radical polymerization (ATRP) in a two‐step or three‐step reaction sequence, respectively. In the first step, a polystyrene (PSt) macroinitiator with dual ω‐bromo functionality was obtained by SFRP of styrene (St) in bulk at 125 °C. Next, this PSt precursor was used as a macroinitiator for ATRP of tert‐butyl acrylate (tBA) in the presence of Cu(I)Br and pentamethyldiethylenetriamine at 80 °C, affording miktoarm star (PSt)(PtBA)2 [where PtBA is poly(tert‐butyl acrylate)]. In the third step, the obtained St(tBA)2 macroinitiator with two terminal bromine groups was further polymerized with methyl methacrylate by ATRP, and this resulted in (PSt)(PtBA)2(PMMA)2‐type miktoarm star block copolymer [where PMMA is poly(methyl methacrylate)] with a controlled molecular weight and a moderate polydispersity (weight‐average molecular weight/number‐average molecular weight < 1.38). All polymers were characterized by gel permeation chromatography and 1H NMR. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2542–2548, 2003 相似文献
7.
Weidong Zhang Wei Zhang Nianchen Zhou Jian Zhu Zhenping Cheng Xiulin Zhu 《Journal of polymer science. Part A, Polymer chemistry》2009,47(22):6304-6315
The novel trifunctional initiator, 1‐(4‐methyleneoxy‐2,2,6,6‐tetramethylpip‐eridinoxyl)‐3,5‐bi(bromomethyl)‐2,4,6‐trimethylbenzene (TEMPO‐2Br), was successfully synthesized and used to prepare the miktoarm star amphiphilic poly(styrene)‐(poly(N‐isopropylacrylamide))2 (PS(PNIPAAM)2) via combination of atom transfer radical polymerization (ATRP) and nitroxide‐mediated radical polymerization (NMRP) techniques. Furthermore, the star amphiphilic block copolymer, poly (styrene)‐(poly(N‐isopropylacrylamide‐b‐4‐vinylpyridine))2 (PS(PNIPAAM‐b‐P4VP)2), was also prepared using PS(PNIPAAM)2 as the macroinitiator and 4‐vinylpyridine as the second monomer by ATRP method. The obtained polymers were well‐defined with narrow molecular weight distributions (Mw/Mn ≤ 1.29). Meanwhile, the self‐assembly behaviors of the miktoarm amphiphilic block copolymers, PS(PNIPAAM)2 and PS(PNIPAAM‐b‐P4VP)2, were also investigated. Interestingly, the aggregate morphology changed from sphere‐shaped micelles (4.7 < pH < 3.0) to a mixture of spheres and rods (1.0 < pH < 3.0), and rod‐shaped nanorods formed when pH value was below 1.0. The LCST of PS(PNIPAAM)2 (pH = 7) was about 31 °C and the LCST of PS(PNIPAAM‐b‐P4VP)2 was about 35 °C (pH = 3). © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6304–6315, 2009 相似文献
8.
Chun Feng Zhong Shen Lina Gu Sen Zhang Litao Li Guolin Lu Xiaoyu Huang 《Journal of polymer science. Part A, Polymer chemistry》2008,46(16):5638-5651
A series of well‐defined double hydrophilic graft copolymers, consisting of poly(N‐isopropylacrylamide)‐b‐poly(ethyl acrylate) (PNIPAM‐b‐PEA) backbone and poly(2‐(diethylamino)ethyl methacrylate) (PDEA) side chains, were synthesized by successive atom transfer radical polymerization (ATRP). The backbone was firstly prepared by sequential ATRP of N‐isopropylacrylamide and 2‐hydroxyethyl acrylate at 25 °C using CuCl/tris(2‐(dimethylamino)ethyl)amine as catalytic system. The obtained diblock copolymer was transformed into macroinitiator by reacting with 2‐chloropropionyl chloride. Next, grafting‐from strategy was employed for the synthesis of poly(N‐isopropylacrylamide)‐b‐[poly(ethyl acrylate)‐g‐poly(2‐(diethylamino)ethyl methacrylate)] (PNIPAM‐b‐(PEA‐g‐PDEA)) double hydrophilic graft copolymer. ATRP of 2‐(diethylamino)ethyl methacrylate was initiated by the macroinitiator at 40 °C using CuCl/hexamethyldiethylenetriamine as catalytic system. The molecular weight distributions of double hydrophilic graft copolymers kept narrow. Thermo‐ and pH‐responsive micellization behaviors were investigated by fluorescence spectroscopy, 1H NMR, dynamic light scattering, and transmission electron microscopy. Unimolecular micelles with PNIPAM‐core formed in acidic environment (pH = 2) with elevated temperature (≥32 °C); whereas, the aggregates turned into vesicles in basic surroundings (pH ≥ 7.2) at room temperature. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5638–5651, 2008 相似文献
9.
Chun Feng Zhong Shen Yongjun Li Lina Gu Yaqin Zhang Guolin Lu Xiaoyu Huang 《Journal of polymer science. Part A, Polymer chemistry》2009,47(7):1811-1824
A series of well‐defined double‐hydrophilic graft copolymers, consisting of poly(N‐isopropylacrylamide)‐b‐poly(ethyl acrylate) (PNIPAM‐b‐PEA) backbone and poly(2‐(dimethylamino)ethyl acrylate) (PDMAEA) side chains, were synthesized by the combination of single‐electron‐transfer living radical polymerization (SET‐LRP) and atom‐transfer radical polymerization (ATRP). PNIPAM‐b‐PEA backbone was first prepared by sequential SET‐LRP of N‐isopropylacrylamide and 2‐hydroxyethyl acrylate at 25 °C using CuCl/tris(2‐(dimethylamino)ethyl)amine as catalytic system followed by the transformation into the macroinitiator by treating the pendant hydroxyls with 2‐chloropropionyl chloride. The final graft copolymers with narrow molecular weight distributions were synthesized by ATRP of 2‐(dimethylamino)ethyl acrylate initiated by the macroinitiator at 40 °C using CuCl/tris(2‐(dimethylamino)ethyl)amine as catalytic system via the grafting‐from strategy. These copolymers were employed to prepare stable colloidal gold nanoparticles with controlled size in aqueous solution without any external reducing agent. The morphology and size of the nanoparticles were affected by the length of PDMAEA side chains, pH value, and the feed ratio of the graft copolymer to HAuCl4. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1811–1824, 2009 相似文献
10.
Chun Feng Zhong Shen Dong Yang Yaogong Li Jianhua Hu Guolin Lu Xiaoyu Huang 《Journal of polymer science. Part A, Polymer chemistry》2009,47(17):4346-4357
A series of well‐defined ferrocene‐based amphiphilic graft copolymers, consisting of poly(N‐isopropylacrylamide)‐b‐poly(ethyl acrylate) (PNIPAM‐b‐PEA) backbone and poly(2‐acryloyloxyethyl ferrocenecarboxylate) (PAEFC) side chains, were synthesized by the combination of single‐electron‐transfer living radical polymerization (SET‐LRP) and atom transfer radical polymerization (ATRP). A new ferrocene‐based monomer, 2‐(acryloyloxy)ethyl ferrocenecarboxylate (AEFC), was prepared first and it can be polymerized via ATRP in a controlled way using methyl 2‐bromopropionate as initiator and CuBr/PMDETA as catalytic system in DMF at 40 °C. PNIPAM‐b‐PEA backbone was synthesized by sequential SET‐LRP of NIPAM and HEA at 25 °C using CuCl/Me6TREN as catalytic system followed by the transformation into the macroinitiator by treating the pendant hydroxyls with α‐bromoisobutyryl bromide. The targeted well‐defined graft copolymers with narrow molecular weight distributions (Mw/Mn < 1.20) were synthesized via ATRP of AEFC initiated by the macroinitiator. The electro‐chemical behaviors of PAEFC homopolymer and PNIPAM‐b‐(PEA‐g‐PAEFC) graft copolymer were studied by cyclic voltammetry. Micellar properties of PNIPAM‐b‐(PEA‐g‐PAEFC) were investigated by transmission electron microscopy and dynamic light scattering. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4346–4357, 2009 相似文献
11.
Aziz Gozgen Aydan Dag Hakan Durmaz Okan Sirkecioglu Gurkan Hizal Umit Tunca 《Journal of polymer science. Part A, Polymer chemistry》2009,47(2):497-504
A combination of ring opening metathesis polymerization (ROMP) and click chemistry approach is first time utilized in the preparation of 3‐miktoarm star terpolymer. The bromide end‐functionality of monotelechelic poly(N‐butyl oxanorbornene imide) (PNBONI‐Br) is first transformed to azide and then reacted with polystyrene‐b‐poly(methyl methacrylate) copolymer with alkyne at the junction point (PS‐b‐PMMA‐alkyne) via click chemistry strategy, producing PS‐PMMA‐PNBONI 3‐miktoarm star terpolymer. PNBONI‐Br was prepared by ROMP of N‐butyl oxanorbornene imide (NBONI) 1 in the presence of (Z)‐but‐2‐ene‐1,4‐diyl bis(2‐bromopropanoate) 2 as terminating agent. PS‐b‐PMMA‐alkyne copolymer was prepared successively via nitroxide‐mediated radical polymerization (NMP) of St and atom transfer radical polymerization (ATRP) of MMA. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 497–504, 2009 相似文献
12.
Xiaolan Luo Guowei Wang Junlian Huang 《Journal of polymer science. Part A, Polymer chemistry》2009,47(1):59-68
H‐shaped ABCAB terpolymers composed of polystyrene (PS) (A), poly(ethylene oxide) (PEO) (B), and poly(tert‐butyl acrylate) (PtBA) (C) were prepared by atom transfer radical coupling reaction using ABC star terpolymers as precursors, CuBr and N,N,N′,N″,N″‐pentamethyldiethylenetriamine (PMDETA) as catalysts, and nanosize copper as the reducing agent. The synthesis of 3‐miktoarm star terpolymer PS‐PEO‐(PtBA‐Br) involved following steps: (1) the preparation of PS with an active and an ethoxyethyl‐ptotected hydroxyl group at the same end; (2) the preparation of diblock copolymer PS‐b‐PEO with ethoxyethyl‐protected group at the junction point through the ring‐opening polymerization (ROP) of EO; (3) after de‐protection of ethoxyethyl group and further modification of hydroxyl group, tBA was polymerized by atom transfer radical polymerization using PS‐b‐PEO with 2‐bromoisobutyryl functional group as macroinitiator. The H‐shaped terpolymer could be successfully formed by atom transfer radical coupling reaction in the presence of small quantity of styrene, CuBr/PMDETA, and Cu at 90 °C. The copolymers were characterized by SEC, 1H NMR, and FTIR in detail. The optimized coupling temperature is 90 °C. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 59–68, 2009 相似文献
13.
The syntheses of well‐defined 7‐arm and 21‐arm poly(N‐isopropylacrylamide) (PNIPAM) star polymers possessing β‐cyclodextrin (β‐CD) cores were achieved via the combination of atom transfer radical polymerization (ATRP) and click reactions. Heptakis(6‐deoxy‐6‐azido)‐β‐cyclodextrin and heptakis[2,3,6‐tri‐O‐(2‐azidopropionyl)]‐β‐cyclodextrin, β‐CD‐(N3)7 and β‐CD‐(N3)21, precursors were prepared and thoroughly characterized by nuclear magnetic resonance and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry. A series of alkynyl terminally functionalized PNIPAM (alkyne‐PNIPAM) linear precursors with varying degrees of polymerization (DP) were synthesized via atom transfer radical polymerization (ATRP) of N‐isopropylacrylamide using propargyl 2‐chloropropionate as the initiator. The subsequent click reactions of alkyne‐PNIPAM with β‐CD‐(N3)7 and β‐CD‐(N3)21 led to the facile preparation of well‐defined 7‐arm and 21‐arm star polymers, namely β‐CD‐(PNIPAM)7 and β‐CD‐(PNIPAM)21. The thermal phase transition behavior of 7‐arm and 21‐arm star polymers with varying molecular weights were examined by temperature‐dependent turbidity and micro‐differential scanning calorimetry, and the results were compared to those of linear PNIPAM precursors. The anchoring of PNIPAM chain terminal to β‐CD cores and high local chain density for star polymers contributed to their considerably lower critical phase separation temperatures (Tc) and enthalpy changes during phase transition as compared with that of linear precursors. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 404–419, 2009 相似文献
14.
Li‐Ying Li Wei‐Dong He Wen‐Tao Li Ke‐Ren Zhang Ting‐Ting Pan Zong‐Lei Ding Bo‐Yu Zhang 《Journal of polymer science. Part A, Polymer chemistry》2010,48(22):5018-5029
Well‐defined H‐shaped pentablock copolymers composed of poly(N‐isopropylacrylamide) (PNIPAM), poly(N,N‐dimethylaminoethylacrylamide) (PDMAEMA), and poly(ethylene glycol) (PEG) with the chain architecture of (A/B)‐b‐C‐b‐(A/B) were synthesized by the combination of single‐electron‐transfer living radical polymerization, atom‐transfer radical polymerization, and click chemistry. Single‐electron‐transfer living radical polymerization of NIPAM using α,ω azide‐capped PEG macroinitiator resulted in PNIPAM‐b‐PEG‐b‐PNIPAM with azide groups at the block joints. Atom‐transfer radical polymerization of DMAEMA initiated by propargyl 2‐chloropropionate gave out α‐capped alkyne‐PDMAEMA. The H‐shaped copolymers were finally obtained by the click reaction between PNIPAM‐b‐PEG‐b‐PNIPAM and alkyne‐PDMAEMA. These copolymers were used to prepare stable colloidal gold nanoparticles (GNPs) in aqueous solution without any external reducing agent. The formation of GNPs was affected by the length of PDMAEMA block, the feed ratio of the copolymer to HAuCl4, and the pH value. The surface plasmon absorbance of these obtained GNPs also exhibited pH and thermal dependence because of the existence of PNIAPM and PDAMEMA blocks. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010 相似文献
15.
Cheng‐Guang Mu Xiao‐Dong Fan Wei Tian Yang Bai Zhen Yang Hao Yao Heng Chen 《Journal of polymer science. Part A, Polymer chemistry》2013,51(6):1405-1416
We report on the synthesis of an H‐shaped polymer bonding β‐cyclodextrin (β‐CD) at branch points and influences of attached β‐CD on physical properties. First, a poly(ethylene glycol)(PEG)‐based functional macroinitiator bearing two azidos and four chlorines at chain‐ends (PEG‐2N3(‐4Cl)) was prepared via terminal modification reactions. Then, PEG‐2N3(‐4Cl) was applied to initiate the atom transfer radical polymerization of N‐isopropylacrylamide, leading to the synthesis of an H‐shaped block polymer with PEG as the central chain and poly(N‐isopropylacrylamide) (PNIPAM) as side‐arms (PEG‐2N3(‐4PNIPAM)). Azido groups were at the branch points of the polymer. Finally, the click reaction between PEG‐2N3(‐4PNIPAM) and alkynyl monosubstituted β‐cyclodextrin (β‐CD) afforded another H‐shaped polymer with two β‐CDs bonding at the polymer branch points (PEG‐2CD(‐4PNIPAM)). The glass transition temperature (Tg) and lower critical solution temperature (LCST) of the H‐shaped polymer increased after the attachment of β‐CD. The self‐assembly and thermal responsive behaviors, as well as the encapsulation behaviors of PEG‐2CD(‐4PNIPAM) were also altered. When temperature was below the LCSTs, PEG‐2N3(‐2PNIPAM) dissolved in water molecularly, whereas PEG‐2CD(‐4PNIPAM) could self‐assemble into nano‐sized micelles. After the LCST transitions, PEG‐2N3(‐4PNIPAM) aggregated into micron‐sized unstable particles, whereas PEG‐2CD(‐4PNIPAM) transformed into PNIPAM‐cored nanomicelles. Besides, PEG‐2CD(‐4PNIPAM) can encapsulate doxorubicin below its LCST due to the formation of micelles. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 相似文献
16.
Eda Gungor Cigdem Bilir Hakan Durmaz Gurkan Hizal Umit Tunca 《Journal of polymer science. Part A, Polymer chemistry》2009,47(22):5947-5953
Azidopropyl‐heptaisobutyl‐substituted polyhedral oligomeric silsesquioxane (POSS‐N3) was reacted with 1,1,1‐tris[4‐(2‐propynyloxy)phenyl]‐ethane ( 1 ) and poly(ethylene glycol) (PEG)‐b‐poly(methyl methacrylate) (PMMA) copolymer with alkyne at its center (PEG‐PMMA‐alkyne) affording the first time synthesis of 3‐arm star POSS and PEG‐PMMA‐POSS 3‐miktoarm star terpolymer, respectively, in the presence of CuBr/N,N,N′,N″,N″‐pentamethyldiethylenetriamine as catalyst and N,N‐dimethylformamide/tetrahydrofuran as solvent at room temperature. The precursors and the target star polymers were characterized comprehensively by 1H NMR, GPC, and DSC. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5947–5953, 2009 相似文献
17.
Jun Yin Zhishen Ge Hao Liu Shiyong Liu 《Journal of polymer science. Part A, Polymer chemistry》2009,47(10):2608-2619
We report on the synthesis of well‐defined amphiphilic copolymer brushes possessing alternating poly(methyl methacrylate) and poly(N‐isopropylacrylamide) grafts, poly(PMMA‐alt‐PNIPAM), via a combination of atom transfer radical polymerization (ATRP) and click reaction (Scheme 1 ). Firstly, the alternating copolymerization of N‐[2‐(2‐bromoisobutyryloxy)ethyl]maleimide (BIBEMI) with 4‐vinylbenzyl azide (VBA) affords poly(BIBEMI‐alt‐VBA). Bearing bromine and azide moieties arranged in an alternating manner, multifunctional poly(BIBEMI‐alt‐VBA) is capable of initiating ATRP and participating in click reaction. The subsequent ATRP of methyl methacrylate (MMA) using poly(BIBEMI‐alt‐VBA) as the macroinitiator leads to poly(PMMA‐alt‐VBA) copolymer brush. Finally, amphiphilic poly(PMMA‐alt‐PNIPAM) copolymer brush bearing alternating PMMA and PNIPAM grafts is synthesized via the click reaction of poly(PMMA‐alt‐VBA) with an excess of alkynyl‐terminated PNIPAM (alkynyl‐PNIPAM). The click coupling efficiency of PNIPAM grafts is determined to be ~80%. Differential scanning calorimetry (DSC) analysis of poly(PMMA‐alt‐PNIPAM) reveals two glass transition temperatures (Tg). In aqueous solution, poly(PMMA‐alt‐PNIPAM) supramolecularly self‐assembles into spherical micelles consisting of PMMA cores and thermoresponsive PNIPAM coronas, which were characterized via a combination of temperature‐dependent optical transmittance, micro‐differential scanning calorimetry (micro‐DSC), dynamic and static laser light scattering (LLS), and transmission electron microscopy (TEM). © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2608–2619, 2009 相似文献
18.
Li Yuan Wulian Chen Jing Li Jianhua Hu Jianjun Yan Dong Yang 《Journal of polymer science. Part A, Polymer chemistry》2012,50(21):4579-4588
A series of well‐defined amphiphilic triblock copolymers, poly(ethylene glycol)‐b‐poly(tert‐butyl acrylate)‐b‐poly(2‐hydroxyethyl methacrylate) (PEG‐b‐PtBA‐b‐PHEMA), were synthesized via successive atom transfer radical polymerization (ATRP). ATRP of tBA was first initiated by PEG‐Br macroinitiator using CuBr/N,N,N′,N″,N′″‐pentamethyldiethylenetriamine as catalytic system to give PEG‐b‐PtBA diblock copolymer. This copolymer was then used as macroinitiator to initiate ATRP of HEMA, which afforded the target triblock copolymer, PEG‐b‐PtBA‐b‐PHEMA. The critical micelle concentrations of obtained amphiphilic triblock copolymers were determined by fluorescence spectroscopy using N‐phenyl‐1‐naphthylamine as probe. The morphology and size of formed aggregates were investigated by transmission electron microscopy and dynamic light scattering, respectively. Finally, an acid‐sensitive PEG‐b‐PtBA‐b‐P(HEMA‐CAD) prodrug via cis‐aconityl linkage between doxorubicin and hydroxyls of triblock copolymers with a high drug loading content up to 38%, was prepared to preliminarily explore the application of triblock copolymer in drug delivery. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
19.
Chen Gao Ying Wang Pengfei Gou Xia Cai Xiaodong Li Weipu Zhu Zhiquan Shen 《Journal of polymer science. Part A, Polymer chemistry》2013,51(13):2824-2833
Well‐defined amphiphilic A8B4 miktoarm star copolymers with eight poly(ethylene glycol) chains and four poly(ε‐caprolactone) arms (R‐8PEG‐4PCL) were prepared using “click” reaction strategy and controlled ring‐opening polymerization (CROP). First, multi‐functional precursor (R‐8N3‐4OH) with eight azides and four hydroxyls was synthesized based on the derivatization of resorcinarene. Then eight‐PEG‐arm star polymer (R‐8PEG‐4OH) was prepared through “click” reaction of R‐8N3‐4OH with pre‐synthesized alkyne‐terminated monomethyl PEG (mPEG‐A) in the presence of CuBr/N,N,N′,N″,N″′‐ pentamethyldiethylenetriamine (PMDETA) in DMF. Finally, R‐8PEG‐4OH was used as tetrafunctional macroinitiator to prepare resorcinarene‐centered A8B4 miktoarm star copolymers via CROP of ε‐caprolactone utilizing Sn(Oct)2 as catalyst at 100 °C. These miktoarm star copolymers could self‐assemble into spherical micelles in aqueous solution with resorcinarene moieties on the hydrophobic/hydrophilic interface, and the particle sizes could be controlled by the ratio of PCL to PEG. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2824–2833. 相似文献
20.
Ozcan Altintas Gurkan Hizal Umit Tunca 《Journal of polymer science. Part A, Polymer chemistry》2008,46(4):1218-1228
Two samples of ABCD 4‐miktoarm star quarterpolymer with A = polystyrene (PS), B = poly(ε‐caprolactone) (PCL), C = poly(methyl methacrylate) (PMMA) or poly(tert‐butyl acrylate) (PtBA), and D = poly(ethylene glycol) (PEG) were prepared using click reaction strategy (Cu(I)‐catalyzed Huisgen [3 + 2] reaction). Thus, first, predefined block copolymers of different polymerization routes, PS‐b‐PCL with azide and PMMA‐b‐PEG and PtBA‐b‐PEG copolymers with alkyne functionality, were synthesized and then these blocks were combined together in the presence of Cu(I)/N,N,N′,N″,N″‐pentamethyldiethylenetriamine as a catalyst in DMF at room temperature to give the target 4‐miktoarm star quarterpolymers. The obtained miktoarm star quarter polymers were characterized by GPC, NMR, and DSC measurements. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1218–1228, 2008 相似文献