文献类型：期刊文献

英文题名：From multi-responsive tri- and diblock copolymers to diblock-copolymer-decorated gold nanoparticles: the effect of architecture on micellization behaviors in aqueous solutions

作者：Song, Lichun;Sun, Hui;Chen, Xiaolu;Han, Xia[1];Liu, Honglai

机构：[1]E China Univ Sci & Technol, Key Lab Adv Mat, Shanghai 200237, Peoples R China; E China Univ Sci & Technol, Dept Chem, Shanghai 200237, Peoples R China

年份：2015

卷号：11

期号：24

起止页码：4830

外文期刊名：SOFT MATTER

收录：;EI(收录号：20152500951143);WOS:【SCI-EXPANDED(收录号:WOS:000356304800009)】；

基金：The authors gratefully acknowledge financial support from the National Natural Science Foundation of China (No. 21176065, 21376073, 91334203), the 111 Project of the Ministry of Education of China (No. B08021), and the Fundamental Research Funds for the Central Universities of China.

语种：英文

外文关键词：Micelles - Metal nanoparticles - Micellization - Acrylic monomers - Atom transfer radical polymerization - Solutions - Sulfur compounds - Fiber optic sensors - Gold nanoparticles

摘要：This work reports on the aqueous stimuli-responsive behaviors of an ABA triblock copolymer, a BAB triblock copolymer, an AB diblock copolymer and citrate-based gold nanoparticles decorated with AB diblock copolymers (where A is the pH-and thermo-responsive poly[N, N-(dimethylamino) ethyl methacrylate] (PDMAEMA) and B is the thermo-responsive poly[2-(2-methoxyethoxy) ethyl methacrylate] (PMEO(2)MA)). The symmetric triblock polymers were synthesized via sequential atom transfer radical polymerization (ATRP) using a disulfide-functionalized initiator. Subsequently, the thiol-ended diblock copolymers were facilely obtained by reducing these triblock copolymers and were grafted onto gold nanoparticle (AuNP) surfaces via ligand exchange to yield stimuli-sensitive gold nanoparticles (Au@AB and Au@BA). The ABA and BAB triblock copolymers exhibited two-step thermo-induced aggregation behavior in water at a pH near the isoelectric point (IEP), which resulted in the formation of micelles after the first lower critical solution temperature (LCST) and large aggregates consisting of clustered micelles above the second LCST transition. The significant difference between the micelle sizes of the ABA and BAB copolymers, such that the micelle size of the BAB copolymer was smaller than that of the ABA copolymer although both had a similar unit composition, suggests a distinction between the micelle structures. The "branch'' and "flower-like'' micelles that are formed in the ABA and BAB aqueous solutions, respectively, ultimately governed the phase transition behaviors. The AB diblock copolymer exhibited similar micellization behavior and a micelle size roughly similar to that of the ABA triblock copolymer, although the chain length of the AB copolymer is only half that of the ABA copolymer. Both Au@PDMAEMA-PMEO(2)MA and Au@PMEO(2)MA-PDMAEMA showed similar dual LCST behaviors and pH-responsive behaviors in aqueous solutions without the addition of salt. A significant difference was observed between the two types of hybrid AuNPs in salty solutions, in which only the Au@PDMAEMAPMEO(2)MA system exhibited thermo-induced aggregation behavior. These hybrid nanoparticles can be used as phase transfer reagents. Additionally, AuNPs capped with PDMAEMA-PMEO(2)MA diblock copolymer can spontaneously transfer across a water-toluene interface.