Enhancing mechanical strength in thermosensitive Poly(tetrabutylphosphonium styrene sulfonate) (PTPSS) hydrogels through acrylamide (AAm) copolymerization

Abstract

Thermosensitive hydrogels are lauded for their smart and tunable responsive behavior, presenting critical application potential in biomedicine and sensing technologies. Traditional thermo-responsive polymers, such as poly(N-isopropylacrylamide) (PNIPAM), typically manifest subpar electrical conductivity, which hinders their integration into biosensing applications. PTPSS hydrogel distinctively responses to temperature and repeatably endures large volume water flux under temperature changes, while catering a significant conductivity (7.438 mS cm−1). However, it possesses suboptimal mechanical strength. In this research, we enhanced the mechanical strength of PTPSS hydrogel by copolymerization of AAm, obtaining a 22-fold increase in compression yield stress and a yield strain reaching up to 75 % The copolymerized hydrogel showcases an elevated transmittance ranging from 86.3–97.1 % within the visible light wavelength spectrum, with the copolymerized hydrogel's conductivity being about 188 times that of PNIPAM copolymerized hydrogel at identical monomer proportions. Simultaneously, the hydrogel maintains explicit thermosensitivity even at a TPSS ratio as low as 60 wt% (grounded on the overall monomer sum). The introduction of AAm copolymerization awards PTPSS with robust mechanical properties, profound transparency, and striking thermosensitivity alongside high conductivity, endorsing enormous potential in the realm of intelligent sensing.