Three-dimensional Layered Water-Soluble Cellulose Acetate/Polyacrylamide Composites with Ultrahigh Ductility and Stretchability.

Water-soluble cellulose acetate (WSCA), one of the most important cellulose derivatives, possesses biocompatibility, biodegradability and broad chemical modifying capacities. In this work, highly polymerized WSCA was firstly synthesized and used as cross-linker to fabricate highly ductile, tough and resilient WSCA/polyacrylamide (PAM) composite hydrogels. The results showed that the WSCA/PAM nanocomposite hydrogels exhibited extraordinary toughness and ductility with a tensile strength of 297 kPa and elongation at break of about 4020%. The enhancement of mechanical properties and stretchability were due to the synergistic effect from the hydrogen bonding and physical entanglement between the composite matrixes. Under stretching conditions, hydrogen bonds and the dense entanglement between WSCA chains and PAM could dynamically break and rearrange to dissipate energy. At the same time, the filaments of PAM embedded in layered WSCA matrix became unfolded or fractured to dissipate energy and maintained the conformation of hydrogels. It was envisioned that the introduction of WSCA into polymeric matrix would generate a facile method to fabricate multiple layered hybrid hydrogel network and significantly widen the WSCA applications in the preparation of high performance supramolecular systems.