Reactive Polymer Brushes Based on Surface-Initiated Reversible Addition-Fragmentation Chain Transfer (SI-RAFT) Polymerization

Abstract

In this paper, we present the synthesis of reactive poly(pentafluorophenyl acrylate) brushes by Surface-Initiated Reversible Addition Fragmentation Chain Transfer (Si-RAFT) polymerization of pentafluorophenyl acrylate (PFPA), which provide the possibility to be converted with primary amines resulting in various functional polymer brushes. These can be used as a platform for fabricating various kinds of thin polymers films by an easy post-modification step. Dithiobenzoic acid benzyl-(4-ethyltrimethoxylsilyl) ester was synthesized as surface-initiated chain transfer agent in order to being attached onto silicon substrates. Finally, reactive polymer brushes with high grafting density and controllable coverage through the grafting-from approach were obtained. Using the prepared reactive polymer brushes, the conversion with an amino-spiropyran resulted in reversible light-responsive polymer brush films. Their wetting behavior could be altered by UV or Vis irradiation, respectively. Furthermore, patterned polymer brushes were obtained by UV irradiation of the SI-CTA modified substrates, resulting in a selective destruction of the chain transfer agent in the irradiated areas, prior RAFT polymerization. Conversion of the patterned polymer brushes with 5-((2-aminoethyl)amino)naphthalene-1-sulfonic acid (EDANS) resulted in patterned fluorescent polymer brush films. In conclusion, the reactive poly(PFPA) brush approach allows the fabrication of various kinds of surfaces by simple conversion with amines, which may result in many applications.

Reactive Polymer Brush, Surface-Initiated RAFT Polymerization, Post Modification, Photo-Patterning, Fluorescent Brushes, Light-Responsive Coating