Development of durable superhydrophobic cotton fabrics coated with silicone/stearic acid using different cross-linkers

Abstract

Nano/micro-scaled surface roughness has been broadly applied for the development of water repellent merchandise. However, the sophisticated procedures, costly and harmful materials employed in the majority of superhydrophobic surface modification techniques have limited their usage. Herein, we develop a mechanically durable superhydrophobic cotton fabric via simple modification of surface roughness using cheap and nontoxic composite. Commercial RTV (Room Temperature Vulcanized) silicone and stearic acid were employed for the surface roughness control. Simple pad-dry-cure and spray-coating approaches were employed to create highly water repellent cotton fabric with high contact angles. Depending on RTV and fatty acid ratio, it was possible to obtain a rough surface with a hierarchical morphology. The stearic fatty acid was admixed with RTV to be effectively applied via both pad-dry-cure and spray-coating techniques onto a pre-treated cotton fabric surface using three different cross-linkers, including citric acid, 3-Isocyanatepropyltriethoxysilane (IPES) and tetraethylorthosilicate (TEOS). The wetting performance was found to depend on the concentration of RTV in toluene as a solvent introducing surface roughness with static water contact angle near to 170° and low sliding angle values as low as 4°. The surface morphological properties of the coated cotton substrates were explored by scanning electron microscopy (SEM). The superhydrophobic performance was investigated employing both of wettability time static water contact angle measurements. The chemical composition of coated cotton substrates was studied employing Fourier-transform infrared spectroscopy (FTIR) and energy-dispersive X-ray analysis (EDAX). Both mechanical and antimicrobial properties of the treated fabrics were investigated. The coated cotton substrates exhibited improved superhydrophobic performance without adversely affecting on its pristine physico-mechanical characteristics. The comfort properties of coated cotton fabrics were also examined by exploring their bending length and air permeability. The results demonstrated durable superhydrophobic performance of the coated samples, presenting a good chance for a large-scale production of superhydrophobic garments for a variety of industrial applications.