One-pot preparation of tough, anti-swelling, antibacterial and conductive multiple-crosslinked hydrogels assisted by phytic acid and ferric trichloride

The flexible biodegradable polymer hydrogels have attracted increasing attention in the exploration of multifarious biomedical applications. However, conveniently achieving the synergistic characteristics of favorable mechanical performance, anti-swelling behavior, antibacterial activity and conductivity into a biodegradable hydrogel remains a significant challenge. In this aspect, we report a facile one-pot approach to prepare the multiple-crosslinked PVA (PVA/PA-Fe) hydrogels assisted by phytic acid (PA) and ferric trichloride. Firstly, PVA polymer chains and PA molecules form hydrogen bonds, meanwhile PA molecules interact with Fe3+ ions by ionic coordinations. Then, PVA polymer chains are crystallized by forming hydrogen bonds after cyclic freeze-thaw process. Based on the synergistic interactions of multiple hydrogen bonds and ionic coordinations in hydrogel system, PVA/PA-Fe hydrogels possess favorable tensile strength (1222.72 kPa), toughness (1.82 MJ/m(3)) and anti-swelling properties. Moreover, the introduction of PA and ferric trichloride successfully endows hydrogel with outstanding antimicrobial activity. Furthermore, the existence of H+ ions ionized by PA, Fe3+ and Cl- ions originating from ferric trichloride provides hydrogel with ionic conductivity (4.91 S/m) and strain responsiveness. Thus, the facile one-pot preparation approach basing on the multiple-crosslinked strategy would broaden the path for preparation of multifunctional hydrogels with promising biomedical applications, particularly smart flexible strain sensors.