A facile route to end-functionalized poly(N-isopropylacrylamide) brushes synthesized by surface-initiated SET-LRP


Turan E., ÇAYKARA T.

REACTIVE & FUNCTIONAL POLYMERS, vol.71, no.11, pp.1089-1095, 2011 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 71 Issue: 11
  • Publication Date: 2011
  • Doi Number: 10.1016/j.reactfunctpolym.2011.08.004
  • Journal Name: REACTIVE & FUNCTIONAL POLYMERS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.1089-1095
  • Keywords: Surface-initiated SET-LRP, Chain transfer agent, Polymer brushes, Hydrophilicity, TRANSFER RADICAL POLYMERIZATION, SILICON-WAFER, 25-DEGREES-C, ACRYLATES, ATRP
  • Gazi University Affiliated: Yes

Abstract

In this study, the facile synthesis of well defined, end-functionalized poly(N-isopropylacrylamide) [poly (NIPAM)] brushes was achieved by surface-initiated single-electron transfer living radical polymerization (SET-LRP). Surface-initiated SET-LRP of N-isopropylacrylamide in the presence of cysteamine chain transfer agent was conducted via Cu(0) generated in situ by the disproportionation of Cu(I) to Cu(0) and Cu(II) in N,N-dimethylformamide at 90 degrees C. Initially, silicon surfaces were modified with 2-bromopropionyl bromide (2-BPB). [Poly(NIPAM)] brushes with amine end-group were then synthesized via surface-initiated SET-LRP from the immobilized 2-BPB. Various characterization techniques including ellipsometry, grazing angle-Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, atomic force microscopy and water contact-angle measurements were used to characterize the immobilization of 2-BPB on the silicon wafer and the subsequent polymer with amine end-group formation. The addition of free 2-BPB initiator was required for the formation of free polymer chains in solution. The free polymer chains were isolated and used to estimate the molecular weights and polydispersity index of chains attached to the surface. Although there are several chemicals methods for post-polymerization transformation of the halide chain end to amine groups, this study mainly provides a method for in situ functionalization of poly(NIPAM) brushes. (C) 2011 Elsevier Ltd. All rights reserved.