TDI/TiO2 Hybrid Networks for Superhydrophobic Coatings with Superior UV Durability and Cation Adsorption Functionality

Durability under UV illumination remains a big challenge of TiO2-based superhydrophobic coatings, with the photocatalytic effect causing degradation of low-surface-energy material over time, resulting in the surfaces losing their hydrophobicity. We report surfaces made from tolylene-2,4-diisocyanate (TDI)/TiO2 hybrid networks that demonstrate superhydrophobicity and superior UV durability. Structural and morphological studies reveal that the TDI/TiO2 hybrid networks are composed of TiO2 nanoparticles interconnected with TDI bridges and then encapsulated by a TDI layer. Through controlling the fraction of TDI in the synthesis process, the thickness of the TDI encapsulation layer around the TDI/TiO2 hybrid networks can be varied. When the weight ratio of TDI/TiO2 is 5:1, the superhydrophobicity of the hybrid network surface remains almost unchanged after a month of continuous UV illumination. This hybrid network surface can also clean methylene blue solution through the synergistic effects of cation adsorpt...