An examination of the anti-icing mechanisms of charged polymer coatings

The adhesion of ice to surfaces can bring about significant safety concerns and operational challenges for aircraft, wind turbines, maritime vessels, power and telecommunications network cables, etc. Whereas active methods of ice removal are often laborious and energy intensive (e.g., heating, applying freezing point depressants, mechanical removal), passive anti-icing coatings rely solely on the chemistry of the surface to suppress ice formation and growth, and reduce the adhesion strength of ice. Numerous different anti-icing surfaces have been developed to this end, with hydrophilic charged polymer surfaces showing considerable promise in reducing the ice adhesion strength. Yet reasoning of the mechanism(s) towards anti-icing properties on these surfaces remains largely inferential.

In this PhD project, the anti-icing mechanisms of charged polymer coatings are investigated. A highly-tailorable coating was developed, with the ability to easily tune the counterions, polymer charge, and crosslink density. Measurements of temperature-dependent ice adhesion strength were accomplished using a home-built test apparatus and were matched to a phase transition in the hydration water of coatings using two independent techniques. Additionally, low temperature ice adhesion was found to correlate the presence of a remaining fraction of hydration water that remains in a “non-freezable” state. These mechanisms and their relationship to the coating properties provide new insights into reducing ice adhesion on charged polymer coatings and can be used to design improved passive anti-icing coatings.