Synthesis and Properties of Gelling Fluoroalkylated End-Capped Oligomers Containing Hydroxy Segments

Abstract

Reactions of fluoroalkanoyl peroxides with 3-methacryloxy-2-hydroxypropyltrimethylammonium chloride (MHPTA) or 2-hydroxy-2-[1-oxoprop-2-enyl)amino]acetic acid (HOPPA) were found to give new fluoroalkylated end-capped oligomers containing 2-hydroxypropyltrimethylammonium or carboxy-hydroxymethylamido segments, respectively, under very mild conditions. These fluoroalkylated end-capped oligomers form a highly viscoelastic fluid (“gel-like”) or cause gelation either in water or in polar organic solvents such as MeOH, EtOH, N,N-dimethylformamide (DMF), and dimethyl sulfoxide (DMSO), whose behavior is governed by the synergistical interactions of strong aggregations of fluoroalkyl segments within oligomers and intermolecular hydrogen bonding between hydroxy or carboxy segments under the non-crosslinked conditions. The fluorinated MHPTA oligomer possessing “gel-like” characteristic was able to reduce the surface tension of water effectively to around 15 mN m−1 with a clear break point, resembling critical micell concentration (CMC). These fluoroalkylated MHPTA oligomer hydrogels had strong metal ion binding or releasing power, and exhibited antibacterial activity to some extent against Staphylococcus aureus. They should thus have high potential for new fluorinated functional materials owing to possessing not only common fluorinated properties such as surface activity and biological activity, but also gelling ability by the aggregation of fluoroalkyl segments.