Highly durable spray layer-by-layer assembled films

Despite the efforts to improve the mechanical durability of layer-by-layer assembled films, abrasion resistance for functional surface applications remains challenging. The authors demonstrate a novel method for significantly improving the abrasion resistance of nanoporous, spray layer-by-layer films by introducing a reinforcing solution containing a sol-gel precursor. The extent of reinforcement depended on the morphology of the film, precursor content in the solution and pretreatment steps. Because both porous films based on silicon dioxide and titanium dioxide nanoparticles were successfully reinforced, the authors combined the materials to create a two-stack antireflection film with significant abrasion resistance while maintaining the desired optical properties. While the fundamental mechanism of reinforcement is not fully understood, the authors have heuristically highlighted the parameters whereby the technique is extensible to other nanoporous systems.