Synthesis of a dual UCST-type thermosensitive and acid-degradable nanogel based on poly(N-acryloyl glycinamide) and a ketal-containing crosslinker

Abstract

In the present study, we designed a dual upper critical solution temperature (UCST) type thermosensitive and acid-degradable nanogel via UV-light initiated RAFT-mediated polymerization-induced thermal self-assembly (PITSA). The dual stimuli-triggered nanogel was prepared with N-acryloyl glycinamide as the precursor monomer of a hydrogen-bonding UCST-type thermosensitive polymer, a new pH-sensitive ketal-containing crosslinker, and poly(poly(ethylene glycol) methyl ether acrylate) acting as both a macromolecular chain transfer agent and a surfactant, called macro-transurf. The resulting spherical nanogel exhibits dual thermo- and pH-sensitive properties, as determined by UV–Vis spectrophotometry and/or dynamic light scatterring measurements at different values of pH (4, 6 and 9) and temperature (5 and 55 °C). The nanogel displays a UCST phase transition at 41 °C in buffer solution (pH = 9) and is degraded rapidly (25 and 45 min) in acidic environments (pH 4 and pH 6).