Highly Stretchable And Self-healing Hydrogels Based On Poly(Acrylic Acid) And Silica Nanoparticles

Polyhedral oligomeric silsesquioxane (POSS) are organic-inorganic hybrid nanomaterials with good mechanical properties, electrical properties, thermal properties, biocompatibilities and so on. Introducing POSS into polymers is an effective way to improve the properties of materials. For conventional hydrogels, their applications are often limited by the weak mechanical strength, much attention have been paid to the development of hydrogels with enhanced mechanical properties. Considering the poor mechanical properties of the chemical crosslinked poly(acrylic acid) (PAA) hydrogels, we introduced POSS into the hydrogels network, high stretchable and self-healing PAA/POSS hybrid hydrogels were prepared. These hydrogles have potential applications in tissue engineering and other biomedical fields.In this study, water-soluble POSS-AH nanoparticles were synthesized via hydrolysis condensation, then the hybrid hydrogels were developed by in situ crosslinking of the self-assembled colloidal PAA/functionalized POSS micelles. Firstly, the effects of POSS-AH on mechanical properties of hydrogels were studied by changing the ratios of POSS-AH to PAA. Secondly, in order to determine the mechanical performance of the PAA/POSS hydrogels, different hydrogels were prepared by changing the proportion of physical and chemical cross-linkers in network. The hydrogels could stretch beyond 4200% than their initial length and the tensile strength was 0.1-0.25MPa. Furthermore, the hydrogel was insensitive to notch. Even for the samples containing V-notches, a stretch of 2300% was demonstrated. Finally, the self-healing properties of the hybrid hydrogels were also examined, and the tensile tests indicated that the hydrogles displayed good self-healing ability. The fracture stress after 96 h healing was 95% of the original uncut hydrogels.