Design and preparation of icephobic PDMS-based coatings by introducing an aqueous lubricating layer and macro-crack initiators at the ice-substrate interface

Abstract

Preventing ice accretion on exposed surfaces is important to the operational performance of various facilities and devices. As time elapses and temperature lowers sufficiently, ice accretion becomes inevitable. Herein, we present a new approach to prepare icephobic coatings by incorporating two strategies towards lowering ice adhesion strength, i.e. introducing an aqueous lubricating layer and maximizing macro-crack initiators at the ice-substrate interface. The aqueous lubricating layer is realized by grafting poly(acrylic acid) (PAA) onto polydimethylsiloxane (PDMS) coatings, and the macro-crack initiators are induced by introducing macro-scale hollow sub-surface structures into PDMS coatings. By using vertical shear tests, ice adhesion strengths of PAA-g-PDMS (10:1), PDMS coatings with macro-scale hollow sub-surface structures (hPDMS) (10:1), PAA-g-hPDMS (10:1), PAA-g-PDMS (10:10), hPDMS (10:10), and PAA-g-hPDMS (10:10) coatings are obtained as 178.5 ± 22 kPa, 153.1 ± 19 kPa, 122.7 ± 18 kPa, 24.6 ± 4 kPa, 20.3 ± 3.4 kPa and 17.6 ± 3.2 kPa, respectively, showing a reduction of 37.2 %, 46.1 %, 56.8 %, 32.8 %, 44.5 % and 51.9 % when compared with corresponding pure PDMS coatings. These results indicate that ice adhesion strength can be further reduced by simultaneously introducing two strategies. The principle of designing icephobic coatings by combining two or more strategies to reduce ice adhesion to as low as possible provides a new avenue to the preparation of icephobic coatings, and makes practical applications possible under extremely severe conditions.