High modulus, fluorine-free self-healing anti-smudge coatings

Abstract

Reported herein is a simple strategy for the fabrication of phenolic polyurethane coatings with self-healing and anti-smudge properties as well as good mechanical strength and optical clarity. Polydimethylsiloxane (PDMS) is incorporated to impart anti-smudge performance into urethane matrix comprised of biobased propyl gallate, hexamethylene diisocyanate trimer, and polytetrahydrofuran prepolymer. Propyl gallate is used as a reversible crosslinker to impart the self-healing properties to the coating. The reaction products were confirmed by Fourier transform infrared spectroscopic studies. Optical microscopic analysis was used to observe the self-healing behavior of polymer films. The contact angle and sliding angle tests were used to evaluate the anti-smudge ability of these polymers. Tensile test, hardness, and abrasion test were used to validate the mechanical properties of the coatings. The obtained coatings showed excellent anti-smudge properties as evident from their water, oil, ink, and hexadecane repellencies. Also, these coatings showed excellent optical clarity approach 100% transmittance. Furthermore, these coatings exhibit promising self-healing properties, which recover from 40 μm cuts in ∼10 min at 120 ℃ and in 1 h at 80 ℃. As this approach offers a simple route towards multi-functional coatings, therefore, real-world applications are anticipated for the coatings reported in this study.