Construction of Multifunctional Composite Films with Biomimetic Bridging and Stress Dissipation Properties

Strategies based on biodegradable polymers to replace traditional petroleum-based plastics have become research hotspots, while designing multifunctional composite films as packaging materials remains a challenging task. Herein, mussel-inspired hollow mesoporous polydopamine (HMPDA) is prepared and used as a secondary reaction platform to immobilize silver nanoparticles (HMPDA@Ag), which are then co-doped into a polyvinyl alcohol (PVA) matrix in combination with naturally derived 2D montmorillonite (MMT). Benefiting from the noncovalent interactions between the composite particles and MMT with the PVA matrix, as well as the synergistic effects between nanofillers, the fabricated films exhibit a great tensile strength of 424.7 MPa, a high toughness of 1093.7 MJ m^-3, and a significantly improved water barrier property. HMPDA@Ag nanoparticles endow the film with excellent properties such as a photothermal synergistic antibacterial effect, ultraviolet shielding, and antioxidation. Additionally, the developed films exhibit significantly improved flame retardancy. Compared with pure PVA, the reduction in peak heat release rate (PHRR) and total heat release (THR) reaches 8.2% and 19.5%, respectively, alongside a notable inhibition of smoke release and melt dripping behavior. This work provides a novel idea for manufacturing multifunctional PVA-based composite films to reduce the environmental impact resulting from the excessive use of non-biodegradable, petroleum-based packaging materials worldwide.