Free-standing interpenetrating PVA-PEGDA films with excellent antifogging performance and mechanical robustness

Robust antifogging films have significant potential for a wide range of applications on the surfaces of transparent materials. Nevertheless, currently either their preparation methods are complex or their mechanical properties such as hardness, wear, scrub and water resistance are yet to be improved before they can be applied in practical applications. In this work, we have developed a facile room temperature approach to fabricating free-standing films of excellent antifogging properties and mechanical robustness. Glutaraldehyde (GA) was used to cross-link polyvinyl alcohol (PVA) and ultraviolet (UV) light was applied to initiate polymerization of poly (ethylene glycol) diacrylate (PEGDA), leading to robust interpenetrating networks (IPN). The films also had excellent mechanical properties with pencil hardness up to 8H, Taber wear-resistance up to 10,000 cycles, and sponge scrub resistance up to 300 cycles. The tensile strength and tearing strength of films reached as high as 100 MPa and 700 kN/m, respectively, much higher than those of free-standing films reported so far. This approach may hold great potential for broad application on various substrates, particularly those with low glass transition temperatures (e.g., transparent plastic films). It may expand the possibilities for future applications of free-standing antifogging films for screens, optical lenses and so on.