Waterborne Nonfluorinated Superhydrophobic Coatings with Exceptional Mechanical Durability Based on Natural Nanorods

Abstract

AbstractPractical applications of superhydrophobic coatings are hindered by some issues, such as harmful chemicals, low mechanical durability, complicated methods, and expensive building blocks, etc. This study reports preparation of waterborne nonfluorinated superhydrophobic coatings with exceptional mechanical durability based on natural nanorods, palygorskite (PAL). A polyurethane (PU) aqueous solution and the homogeneous methyl polysiloxane‐modified PAL (PAL@M‐POS) suspension composed of methyltrimethoxysilane and the PAL nanorods in water are layer‐by‐layer spray‐coated onto glass slides for two times with PU as the adhesive layer. The PAL@M‐POS suspensions and the superhydrophobic PU/PAL@M‐POS coatings are studied using various analytical techniques. The influences of PAL and methyltrimethoxysilane on microstructure, wettability, and mechanical durability of the coatings are also investigated. The PU/PAL@M‐POS coatings feature high water contact angle (157.9°), low sliding angle (7.2°), and exceptional mechanical durability against sandpaper abrasion for 80 m and peeling with adhesive tape for 100 cycles. The mechanism behind the high mechanical durability is proposed. Also, the totally green method is simple, low‐cost, scalable, and applicable onto various substrates, which have paved the way for practical applications of the durable superhydrophobic coatings. This work provides a new avenue for the fabrication of waterborne, nonfluorinated, and mechanically durable superhydrophobic coatings using abundant natural nanomaterials.