Morphology Evolution of Polystyrene-core/Poly(N-isopropylacrylamide)-shell Microgel Synthesized by One-pot Polymerization  

作　　者：Wen-tao Hu Hua Yang 程贺 胡海青 

机构地区：[1]Key Laboratory of Rubber-Plastics,Ministry of Education/Shandong Provincial Key Laboratory of Rubber-Plastics,School of Polymer Science and Engineering,Qingdao University of Science and Technology,Qingdao 266042,China [2]China Spallation Neutron Source(CSNS),Institute of High Energy Physics(IHEP),Chinese Academy of Sciences(CAS),Dongguan 523803,China [3]Dongguan Institute of Neutron Science(DINS),Dongguan 523808,China

出　　处：《Chinese Journal of Polymer Science》2017年第9期1156-1164,共9页高分子科学（英文版）

基　　金：This work was financially supported by the National Natural Science Foundation of China(Nos.21474119 and 21674020)

摘　　要：One-pot polymerization with macroinitiator is supposed to be a robust, facile way to synthesize well-defined core- shell nanoparticles with fixed shell thickness. To testify this, we investigated the temperature-depending morphology evolution of polystyrene （PS） core/poly（N-isopropylacrylamide） （PNIPAM） shell microgel synthesized by one-pot polymerization with PNIPAM-RAFT as macroinitiator in dimethylformamide （DMF） by transmission electron microscopy （TEM）, dynamic/static light scattering （DLS/SLS） and small angle neutron scattering （SANS）. It is revealed that the microgel has a core-shell structure, i.e., the core is made of pure PS, but the shell is composed of both PNIPAM-RAFT macroinitiator and crosslinked PS. In fact, there are 92.0 wt% D20, 6.7 wt% PNIPAM and 1.3 wt% PS in the shell in its aqueous dispersion at 21 ℃; therefore, its shell thickness is much larger than the extended chain length of the macroinitiator as revealed by both SANS and DLS observations. Competitive growth of styrene, divinylbenzene and PNIPAM macroinitiator as well as possible chain transfer from amine proton of PNIPAM side chain may lead to the larger shell thickness, compared with the extended chain length of the macroinitiator. Our work can shed light on the real morphology control in one-pot polymerization.One-pot polymerization with macroinitiator is supposed to be a robust, facile way to synthesize well-defined core- shell nanoparticles with fixed shell thickness. To testify this, we investigated the temperature-depending morphology evolution of polystyrene （PS） core/poly（N-isopropylacrylamide） （PNIPAM） shell microgel synthesized by one-pot polymerization with PNIPAM-RAFT as macroinitiator in dimethylformamide （DMF） by transmission electron microscopy （TEM）, dynamic/static light scattering （DLS/SLS） and small angle neutron scattering （SANS）. It is revealed that the microgel has a core-shell structure, i.e., the core is made of pure PS, but the shell is composed of both PNIPAM-RAFT macroinitiator and crosslinked PS. In fact, there are 92.0 wt% D20, 6.7 wt% PNIPAM and 1.3 wt% PS in the shell in its aqueous dispersion at 21 ℃; therefore, its shell thickness is much larger than the extended chain length of the macroinitiator as revealed by both SANS and DLS observations. Competitive growth of styrene, divinylbenzene and PNIPAM macroinitiator as well as possible chain transfer from amine proton of PNIPAM side chain may lead to the larger shell thickness, compared with the extended chain length of the macroinitiator. Our work can shed light on the real morphology control in one-pot polymerization.

关 键 词：ONE-POT PS-core/PNIPAM-shell TEM DLS SANS 

分 类 号：O648.17[理学—物理化学]