نتایج جستجو برای: prolylene copolymer

تعداد نتایج: 12139  

2014
Tao Kong Lin Ye Ai-ying Zhang Zeng-guo Feng

A pentablock copolymer was prepared via the atom transfer radical polymerization of 2-hydroxyethyl methacrylate (HEMA) initiated by 2-bromoisobutyryl end-capped PPO-PEO-PPO as a macroinitiator in DMF. Attaching PHEMA blocks altered the self-assembly process of the pentablock copolymer with γ-CDs in aqueous solution. Before attaching the PHEMA, the macroinitiator was preferentially bent to pass ...

Journal: :ACS nano 2011
Bingqi Zhang Yanjie Zhang Surya K Mallapragada Aaron R Clapp

We characterized the dissociation of polymer/DNA polyplexes designed for gene delivery using water-soluble quantum dots (QDs). A pH-responsive pentablock copolymer was designed to form stable complexes with plasmid DNA via tertiary amine segments. Dissociation of the polyplex was induced using chloroquine where the efficiency of this process was sensed through changes in QD fluorescence. We fou...

2015
Michika Onoda Takeshi Ueki Mitsuhiro Shibayama Ryo Yoshida

Here we report an ABA triblock copolymer that can express microscopic autonomous formation and break-up of aggregates under constant condition to generate macroscopic viscoelastic self-oscillation of the solution. The ABA triblock copolymer is designed to have hydrophilic B segment and self-oscillating A segment at the both sides by RAFT copolymerization. In the A segment, a metal catalyst of c...

Journal: :Nature materials 2004
Goundla Srinivas Dennis E Discher Michael L Klein

Block-copolymer amphiphiles have been observed to assemble into vesicles and other morphologies long known for lipids but with remarkably different properties. Coarse-grain molecular dynamics (CG-MD) is used herein to elaborate the structures and properties of diblock copolymer assemblies in water. By varying the hydrophilic/hydrophobic ratio of the copolymer in line with experiment, bilayer, c...

2008
W. Tang

Electrical field-induced strain response of electron-irradiated Poly(viny1idene fluoride trifluoroethylene) copolymer has been studied by a Mach-Zehnder type Heterodyne interferometer in the frequency range of 3 to 9 kHz. The electrostrictive constant is calculated from the strain results, which is of the same order of magnitude as those obtained at 1 Hz by a bimorph-based strain sensor, but at...

Journal: :Langmuir : the ACS journal of surfaces and colloids 2004
Yongzhong Chen Haiying Huang Zhijun Hu Tianbai He

Block copolymers have long been studied for their theories and applications especially in nanotechnology.1-5 They have periodic structures with 10-100 nm long microphase separated domains which can be controlled by the molecular weight and composition of the block copolymer. Regulating these two parameters, one can prepare thin films with different morphologies over large areas. The patterns fo...

2012
Andreja Eršte Vid Bobnar Xian-Zhong Chen Cheng-Liang Jia Qun-Dong Shen

We report structural, caloric, and dielectric properties of polymer blends of poly(vinylidenefluoride–trifluoroethylene–chlorofluoroethylene) terpolymer (a member of the relaxor polymers family that exhibits fast response speeds, giant electrostriction, high electric energy density, and large electrocaloric effect) and poly(vinylidenefluoride–chlorotrifluoroethylene) copolymer, developed on alu...

2006
HE CHENG GUANGMING LIU CHENGQING WANG GUANGZHAO ZHANG CHI WU

Poly(N-isopropylacrylamide-co-sodium acrylate) copolymer brushes grafted on SiO2-coated quartz crystal surface were prepared with a surface-immobilized initiator. The collapse and swelling of the thermally sensitive copolymer brushes in water were studied with quartz crystal microbalance in situ. The frequency and dissipation changes with the temperature increasing in the range 20–38 8C indicat...

Journal: :Biotechnology progress 1991
A Gupte R Nagarajan A Kilara

Block copolymers exhibit the phenomenon of microdomain formation in pure states as well as in solutions. The microdomains vest the block copolymer assemblies with the intriguing characteristics of microheterogeneous media. We demonstrate that this microheterogeneity in hydrophobic-hydrophilic block copolymer systems can be exploited for immobilizing enzymes and to carry out enzymatic reactions....

Journal: :Journal of the American Chemical Society 2015
Dong-Po Song Ying Lin Yue Gai Nicholas S Colella Cheng Li Xiao-Hui Liu Samuel Gido James J Watkins

To date the self-assembly of ordered metal nanoparticle (NP)/block copolymer hybrid materials has been limited to NPs with core diameters (D(core)) of less than 10 nm, which represents only a very small fraction of NPs with attractive size-dependent physical properties. Here this limitation has been circumvented using amphiphilic brush block copolymers as templates for the self-assembly of orde...

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