Bio-based omniphobic polyurethane coating providing anti-smudge and anti-corrosion protection

Herein, a novel omniphobic polyurethane (PU) coating has been prepared from bio-based acetylated starch (ac-Starch) as the polyol and hexamethylene diisocyanate trimer (HDIT) as the cross-linking agent. A small amount of monocarbinol terminated polydimethylsiloxane (PDMS−OH), as a lubricating ingredient, is introduced into the coating through covalent attachment with excess HDIT to prevent large scale phase separation with other coating components. By adjusting PDMS content (0.5–3.0 wt.%), ac-Starch based PU coatings with high transparency (>97 %) and excellent anti-smudge properties are obtained. Specifically, various liquid contaminants such as inks, water- and oil-based substances are easily removed from the coating surface, either through "sliding-off" or "beading" and "wiping-off" without any traces left behind. In addition, these coatings could provide anti-corrosion properties for metal surfaces. Thus, such bio-based "green" coatings with omniphobic properties are promising for protecting surfaces from contamination and corrosion, which is critical for the sustainable development of functional coating materials.