Lotus-effect biomimetic modification of the cotton fabric and its negative ion functionality

In pursuit of achieving the effective negative ion release property for cotton fabric, and to meet the functional requirements of cotton fabric when applied to automotive interiors, which entails environmental purification as well as self-cleaning capabilities. The amino-modified polysiloxane (AMP) was employed for fluorine-free hydrophobic finishing to endow the cotton fabric with hydrophobicity in this study, while forming adhesive structure on the surface of the cotton fabric. The introduction of tourmaline particles (TM) constructed the biomimetic micro-papillary structure like the surface of the lotus leaf. When the concentration of the AMP was 4 wt% and the concentration of the TM was 4 wt%, the modified fabric was imparted with the best comprehensive performance: contact angle of 145.8°, water vapor transmission rate of 5428 g/(m²·24h), air permeability of 434.2 mm/s, maximum force of 175.6 N, and negative ion released of 1640 ions/cm³. Further increasing the concentration of TM to 8 wt%, the fabric was imparted with certain self-cleaning properties (contact angle of 150.3°). In addition, the durability test of cotton fabric modified by 4wt% AMP + 4wt% TM showed that it still had a high contact angle (142.4 °) after 50 times of dry friction, and the release of negative ions increased to 2108 ions/cm³ after 20 times of surface grinding. Through the application of a hydrophobic-negative ion composite coating to the cotton fabric, this research successfully fabricated a modified cotton fabric with superhydrophobicity and negative ion emission capabilities, thus offering broad application prospects of the modified cotton fabric in the automotive interior sector.