Novel Approach for the Preparation of a Highly Hydrophobic Coating Material Exhibiting Self-Healing Properties

Abstract

A concept to prepare a highly hydrophobic composite with self-healing properties has been designed and verified. The new material is based on a composite of a crystalline hydrophobic fluoro wax, synthesized from montan waxes and perfluoroethylene alcohols, combined with spherical silica nanoparticles equipped with a hydrophobic shell. Highly repellent layers were prepared using this combination of a hydrophobic crystalline wax and silica nanoparticles. The novel aspect of our concept was to prepare a ladder-like structure of the hydrophobic shell allowing the inclusion of a certain share of wax molecules. Wax molecules trapped in the hydrophobic structure during mixing are hindered from crystallizing; therefore, these molecules maintain a higher mobility compared to crystallized molecules. When a thin layer of the composite material is mechanically damaged, the mobile wax molecules can migrate and heal the defects to a certain extent. The general preparation of the composite is described and XRD analysis demonstrated that a certain share of wax molecules in the composite are hindered to crystallize. Furthermore, we show that the resulting material can recovery its repellent properties after surface damage.

Keywords

• self-healing
• hydrophobicity
• sol-gel
• silica nanoparticle