Thermoresponsive Poly(α-peptoid)s: Tuning the Cloud Point Temperatures by Composition and Architecture

Abstract

Random copolymers based on poly(<i>N</i>-ethyl glycine) and poly(<i>N</i>-butyl glycine) have been synthesized by NHC-mediated or primary amine-initiated copolymerization of the corresponding <i>N</i>-substituted <i>N</i>-carboxyanhydride monomers (i.e., Et-NCA and Bu-NCA), respectively. The copolymers are thermally responsive and exhibit reversible phase transitions with tunable cloud point temperature (<i>T</i>_cp) in aqueous solution. The <i>T</i>_cp can be readily tuned in the temperature range 20-60 °C by controlling the copoly(α-peptoid) composition and the architecture (i.e., cyclic vs linear). The copoly(α-peptoid)s are noncytotoxic (similar to poly(ethylene glycol) (PEG), a benchmark biocompatible polymer), suggesting their potential use in biotechnology and biomedicine.