Acta Phys. -Chim. Sin. ›› 2012, Vol. 28 ›› Issue (11): 2683-2689.doi: 10.3866/PKU.WHXB201207161

• SOFT MATTER • Previous Articles     Next Articles

Synthesis and Characterization of Temperature-Sensitivity P(MEO2MA-co-OEGMA) Copolymers

LÜ Hai-Yan, LIU Shou-Xin, XU Chao, TIAN Rong, WANG Li   

  1. Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710062, P.R. China
  • Received:2012-05-08 Revised:2012-07-13 Published:2012-10-17
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (20973106), Fundamental Research Funds for the Central Universities, China (GK201001001), and Program for Changjiang Scholars and Innovative Research Team in University of China (IRT1070).

Abstract:

Temperature-responsive P(MEO2MA-co-OEGMA) copolymers of 2-(2-methoxyethoxy) ethyl methacrylate (MEO2MA) and oligo(ethylene glycol) methacrylate (OEGMA) were synthesized via atom transfer radical polymerization (ATRP) in ethanol using CuCl/2,2'-bipyridyl (bpy) as the catalyst system and ethyl-2-bromopropionate (EBP) as an initiator. The synthesized copolymers were characterized by proton nuclear magnetic resonance spectroscopy (1H NMR) and gel permeation chromatography (GPC). Copolymer temperature sensitivities in aqueous solution were investigated by measurements of optical transmittance and viscosity as well as laser particle size analysis. The effects of various parameters on the phase transition temperatures of aqueous copolymer solutions were examined, including OEGMA content, solution concentration, and the concentrations and species of added salts. Results showed that the copolymers demonstrated temperature sensitivity; the lowest critical solution temperature (LCST) increased both with increasing OEGMA content and decreasing solution concentration. Copolymer LCST values could also be controlled by adjusting the mole fractions of MEO2MA and OEGMA. It was additionally observed that LCST values decreased as the salt concentration and anion valence increased. The addition of acid or base also affected the LCST of the copolymer solutions; addition of HCl decreased the LCST while addition of NaOH resulted in an increase.

Key words: P(MEO2MA-co-OEGMA) copolymer, Temperature sensitivity, Atom transfer radical polymerization, Salt effect, pH effect

MSC2000: 

  • O648