Composite coating with superior repellence
Re-entrant geometries can effectively trap air pockets, increase air/liquid interface fraction, prevent the penetration of low surface tension organic liquids, and achieve super-oleophobic performance. However, the creation of re-entrant geometries usually involving expensive lithographic tools, or complicated chemical procedures, and cannot be applied on a large scale.
Constructing hierarchical micro/nanostructure on substrates is a feasible solution to achieve super-oleophobicity through facile spraying method. Scientists report a super-oleophobic TiO2/SiO2 composite coatings by taking advantage of an exceedingly simple spraying method. The dendritic structures produced by spraying the TiO2/SiO2 mixture play the critical role in obtaining the re-entrant geometry required for oleophobic surface, and the introduction of micron-scale TiO2 particles and nano-scale SiO2 particles provide an enough dual-scale rough structure for the coating.
Superior repellence to high and low surface tension liquids
The TiO2/SiO2 composite coatings exhibit superior repellence to high and low surface tension liquids as well long-term durability. According to the researchers, this design strategy may provide useful guidelines for the fabrication of particle-based spray-coated super-oleophobic surfaces.
The study has been published in Progress in Organic Coatings, Volume 159, October 2021.