Strong, Water-Resistant, and Ionic Conductive All-Chitosan Film with a Self-Locking Structure

Renewable and biodegradable natural polymeric materials are attractive candidates for replacing nonbiodegradable plastics. However, it is challenging to fabricate polysaccharide-based materials (such as cellulose and chitin) that can be used in humid or even watery environments due to their inferior stability against water. Here, a self-locking structure is constructed to develop a strong, water-resistant, and ionic conductive all-chitosan film without other additives. The densely packed self-locking structure introduces strong interactions between chitosan nanofibers, preventing the fibers from disentangling even in watery environments. The resulting film exhibits outstanding tensile strength of ∼144 MPa, superior wet strength of ∼54.3 MPa, and high ionic conductivity of 0.0012 S/cm at 10