Facile construction of fluorine-free hydrophobic cotton fabrics by thiol-ene click reaction for oil-water separation

Fabrication of environmental-friendly hydrophobic materials is significantly important but challenging. Herein, utilizing the versatile thiol-ene click reaction, a pre-designed allyl-containing cyclophosphazene (CCPD) was facilely grafted onto the surfaces of organosilicone modified cotton fabrics (MPTES-CFs), and fluorine-free hydrophobic cotton fabrics (CCPD-MPTES-CFs) were fabricated. The structure analyses revealed the successful formation of the cyclophosphazene-based polymeric layer on the surface of cotton fabrics. The static contact angles (CAs) of CCPD-MPTES-CFs were measured, and the results indicated the superhydrophobicity of the clicked fluorine-free CCPD-MPTES-CFs with the CAs of up to 153.6°. CCPD-MPTES-CFs can maintain highly hydrophobic stability even without significant decrease in CAs after immersing in acid and base solutions for 21 days. Additionally, the clicked samples possess good self-cleaning property upon exposure to various liquids. The studies of CCPD-MPTES-CFs in oil-water separation demonstrated the excellent efficiency rate of 98.3 % for n-hexane and 98.2 % for toluene with separation fluxes being of 5720 and 5850 L/(m²⸱h), respectively. This study demonstrated that utilizing the versatile thiol-ene click reaction, fluorine-free hydrophobic cotton fabrics can be facially fabricated by grafting functionalized cyclophosphazene onto their surface.