Non-fluorinated sol-gel processing of hydrophobic coating on cotton fabric

Abstract

In this study, the importance of wash durability tests for providing efficient hydrophobic surfaces through non-fluorinated sol-gel processes has been investigated. Various concentrations of methyltriethoxysilane (MTEOS) and trimethylchlorosilane (TMCS) have been used to deposit SiO₂ nanoparticles on a cotton fabric in a two-step sol-gel process. The effects of catalyst type on the hydrophobic properties of fabric are investigated by using ammonia or hydrochloric acid in the sol-gel procedure. Surface characteristics, such as morphology and wettability are evaluated by image processing techniques and contact angle measurements. Air permeability, mechanical strength and wash durability tests are also performed to investigate the physical/mechanical properties of the samples. The results show that SiO₂ nanoparticles are well dispersed on cotton fabrics with a contact angle of 149^o. It is revealed that the fabric coated with 1 mL of MTEOS and ammonia catalyst exhibits the highest breathability and strength. Moreover, the first stage of the sol-gel technique is sufficient to provide super hydrophobicity. However, the results of the durability test indicate that sol-gel technique does not provide suitable wash durability that should be considered in future investigations.