Self-healing and self-cleaning nanocomposite coatings

This work reports on the introduction of self-cleaning and self-healing properties in polymer/nanoparticle composites. A series of epoxy/halloysite nanotubes (HNTs)/cellulose acetate butyrate (CAB) composites with various CAB concentrations were developed and subjected to different levels of mechanical loading. The optimized concentration of nanoparticle is 1.0 vol% and for CAB concentration of 3.0 vol% based on the mechanical reinforcements and wear-resistance. The addition of CAB can significantly modify the surface chemistry and reduce roll-off angles of water droplets from 90° to 20°, and benefit the self-healing properties. Nanoscale scratching and macro-level Taber Abrasion tests were used to damage the surfaces. The initiated damages of roughness and surface scratch up to hundreds of nanometers were healed upon heating. The water sliding angles and mechanical integrity for epoxy-based composites were reserved after healing, suggesting broad applications in optical systems, energy components, and mechanical parts requiring structural behaviors and multi-functionalities.