Thermoresponsive gelation behavior of poly(N-isopropylacrylamide)-block-poly(N-vinylpyrrolidone)-block-poly(N-isopropylacrylamide) triblock copolymers

•Triblock copolymers of PNIPAM and PVP were synthesized via RAFT polymerization.•The ABA triblock copolymers displayed thermoresponsive gelation behavior.•The triblock copolymers could be used as injectable hydrogels.

In this contribution, we reported the synthesis of poly(N-isopropylacrylamide)-block-poly(N-vinylpyrrolidone)-block-poly(N-isopropylacrylamide) (PNIPAM-b-PVP-b-PNIPAM) triblock copolymers through sequential reversible addition–fragmentation chain transfer/macromolecular design via the interchange of xanthate (RAFT/MADIX) process. The triblock copolymers have been characterized by means of 1H nuclear magnetic resonance (NMR) spectroscopy, gel permeation chromatography (GPC) and differential scanning calorimetry (DSC). This ABA triblock copolymer displayed a typical thermoresponsive gelation behavior. In this work, the thermoresponsive gelation behavior was investigated by means of rheological measurements, micro-differential scanning calorimetry (Micro-DSC) and small angle X-ray scattering (SAXS). The thermoresponsive gelation behavior could endow the triblock copolymers with the potential application as injectable hydrogels.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slide