Ambient curable superhydrophobic fabric coating prepared by water based non fluorinated formulation
Abstract Superhydrophobic coatings can be applied to fabrics to provide water repellent and easy clean properties. Hence, there is an intensive commercial demand for environmentally friendly, cost effective, and scalable technologies of superhydrophobic fabric coatings. Herein, we report a water based and non fluorinated sol gel formulation for ambient curable superhydrophobic fabric coatings. The coating material was prepared by surface modification of silica nanoparticles with (3 aminopropyl) triethoxysilane (APTES) and hexadecyltrimethoxysilane (HDTMS) In this formulation, APTES stabilizes the dispersion of silica nanoparticles in water, and also enhances the adhesion of modified nanoparticles on fabric surfaces. The silica nanoparticles and HDTMS respectively contribute to the superhydrophobic performance by enhancing the surface roughness and reducing the surface free energy. The aqueous coating solution can be applied to fabric surfaces by one step spraying process, and the coating is ambient curable at room temperature. This facilitates scale up applications with simplified treatment processes. Coatings have been applied on various fabrics including polyester, cotton and mixed cotton/polyester. Superhydrophobic properties have been verified for coated cotton and cotton/polyester. Static water contact angles above 150deg with hysteresis around 10deg for 2 mL water droplets have been achieved. The durability of the coating was tested by washing/drying cycles and abrasion cycles.