Ultra-low ice adhesion enabled by nano-engineered poly(ionic liquid)-elastomeric films: leveraging aqueous lubrication and elasticity

Abstract

Ice accumulation poses challenges across diverse industries. For effective passive ice removal, surfaces must achieve ultra-low ice adhesion strength (τ_ice), ideally below 10 kPa. Such low ice adhesion values with persistent functionality are rarely reported. Typically, coatings exhibiting such qualities require increased thicknesses, often in the range of hundreds of microns, thereby compromising scalability. This study introduces novel poly(ionic liquid) (PIL)-based elastomeric thin films, nano-engineered through a unique surface-initiated polymerization technique called solid-state continuous assembly of polymers (ssCAP), incorporating a new amphiphilic PIL-based lubricant (AmL). Nano-scale surface-confined polydimethylsiloxane networks with enhanced elasticity and chain mobility are achieved by precisely controlling the crosslinking density. Addition of 20 wt% AmL to a highly elastic, surface-tethered network imparted a thin PIL-infused film with ultra-low ice adhesion strength τ_ice ∼ 1.4 kPa, showcasing a one-order-of-magnitude reduction in τ_ice. Leveraging elasticity and interfacial aqueous lubrication have led to this passive ice shedding, making this the first instance of such a low value in hydrated coatings. This thin PIL-elastomeric film retained its ice adhesion strength below 10 kPa even after tape peeling, prolonged water exposure, and 15 icing/de-icing cycles. This is likely attributed to the robust ssCAP_ROMP chemistry and rationally designed amphiphilic lubricant ensuring its effective integration within the elastomeric network. Remarkably, the film developed here is only 30 nm thick, obviating the need for the considerable thickness typically required by other soft coatings. This work aims to establish design guidelines for the next generation of thin icephobic coatings, harnessing synergistic design strategies and robust surface chemistries.