Ultra-stretchable and tough polyacrylamide hydrogel reinforced with water-soluble cellulose acetate as a multiple cross-linker

摘要

Water-soluble cellulose acetate WSCA has been used as multifunctional physical cross-linker for the synthesis of super tough,high ductility and resilient WSCA-polyacrylamide(PAM)composite hydrogels.The composite gels can be considered to some extent as double networks:(i)the first cross-linking points are hydrogen bond between PAM chains and WSCA;(ii)the second cross-linking points are the physical3-dimensional network reinforced by WSCA.Under stretching conditions,hydrogen bonds between PAM chains and WSCA could dynamically break and rearrange to dissipate energy,meanwhile,the initial wound fibers between layers or embedded in PAM matrix became unfolded or fractured to dissipate energy and maintain the conformation of hydrogels.In this case,uniaxial tensile tests demonstrated a fracture strain about 4020％,an ultimate stress of 297 kPa.Besides,the these composite gels showed extraordinary fatigue resistance against cyclic loading and the ultrahigh strains could be recovered with low residual strains upon unloading.