Biomass-based functional film integrated with nitrogen-coordinating boronic ester and cellulose-barium titanate nanohybrids

Although renewable and biodegradable biomaterials have received considerable attention as sustainable alternatives to traditional petrochemical plastics, their production and application have been limited due to insufficient mechanical properties and high hydrophilicity. In this study, we report a green and facile strategy for the preparation of a gelatin-based film with enhanced mechanical strength, water resistance, and electrochemical properties. The nitrogen-coordinating boronic ester (BN), prepared from diethanolamine and boronic acid, acted as a dynamic glue linkage. Introducing hydrophobic long-chain fatty acids of stearic acid (SA) formed a cross-linked network with BN and gelatin through bioconjugation, effectively improving the film's water resistance. Moreover, nanofibrillated cellulose assisted the dispersion of BaTiO3 particles as a hybrid enhancement nanophase to enhance the performance of the composite film. The toughness and tensile strength of the as-prepared composites reached 22.35 MJ/m3 and 23.30 MPa, which were 424.6 % and 193.1 % higher than the neat gelatin film. Attractively, incorporating BaTiO3 nanoparticles with a high-dielectric constant endowed the film with excellent electrochemical performance. In addition, the hybrid film exhibited substantially enhanced ultraviolet-blocking properties and thermal stability. This multifunctional gelatin-based film is expected to significantly advance the industrial production and application of biomaterials in hydrogels, adhesives, and coatings.