A chitin nanofibril reinforced multifunctional monolith poly(vinyl alcohol) cryogel

A highly porous and spongy monolith cryogel was prepared by a single freeze-thawing cycle of a PVA solution containing chitin nanofibrils (CNFs) as the nanofiller and glutaraldehyde (GA) as the cross-linker. The presence of CNFs significantly reinforced the spongy structure of the cryogel so that repeated squeezing-releasing did not deteriorate its spongy structure. The in situ self-polymerized polydopamine was formed inside the spongy cryogel by soaking the cryogel in a dopamine solution. The polydopamine modified cryogel (PVA-CNF-D) showed a very good antioxidant activity in that approximately 49% of free radicals of DPPH˙ was consumed within 2 min. Silver nanoparticles (SNPs) could be spontaneously reduced from silver nitrate solution and deposited onto the polydopamine modified surface without an exogenous reducing reagent. The SNP incorporated spongy cryogel demonstrated a very effective antibacterial activity against E. coli.