Designing Durable Icephobic Surfaces

Ice accretion has a negative impact on critical infrastructure, as well as a range of commercial and residential activities. Icephobic surfaces are defined by an ice adhesion strength τ_ice < 100 kPa. However, the passive removal of ice requires much lower values of τ_ice, such as on airplane wings or power lines (τ_ice < 20 kPa). Such low τ_ice values are scarcely reported, and robust coatings that maintain these low values have not been reported previously. Here we show that, irrespective of material chemistry, by tailoring the crosslink density of different elastomeric coatings, and by enabling interfacial slippage, it is possible to systematically design coatings with extremely low ice-adhesion (τ_ice < 0.2 kPa). These newfound mechanisms allow for the rational design of icephobic coatings with virtually any desired ice adhesion strength. We also propose a new model for interfacial slippage, based on Flory-Huggins theory coupled with a Hemi-wicking analysis. Our model not only allows for icephobic elastomers, polymers and monolayers to be systematially designed, but also makes a connection to previous icephobic systems based on lubrication. Utilizing our newfound mechanisms and model, we fabricate extremely durable coatings that maintain τ_ice< 10 kPa after severe mechanical abrasion, acid/base exposure, 100 icing/de-icing cycles, thermal cycling, accelerated corrosion, and exposure to Michigan wintery conditions over several months.

This work was published in Science Advances in March of 2016. DOI: 10.1126/sciadv.1501496.