Multiscale crack initiator promoted super-low ice adhesion surfaces

Abstract

Preventing icing on exposed surfaces is important for life and technology. While suppressing ice nucleation by surface structuring and local confinement is highly desirable and yet to be achieved, a realistic roadmap of icephobicity is to live with ice, but with lowest possible ice adhesion. According to fracture mechanics, the key to lower ice adhesion is to maximize crack driving forces at the ice-substrate interface. Herein, we present a novel integrated macro-crack initiator mechanism combining nano-crack and micro-crack initiators, and demonstrate a new approach to designing super-low ice adhesion surfaces by introducing sub-structures into smooth polydimethylsiloxane coatings. Our design promotes the initiation of macro-cracks and enables the reduction of ice adhesion by at least ∼50% regardless of the curing temperature, weight ratio and size of internal holes, reaching a lowest ice adhesion of 5.7 kPa. The multiscale crack initiator mechanisms provide an unprecedented and versatile strategy towards designing super-low ice adhesion surfaces.

Enhancing the Mechanical Durability of Icephobic Surfaces by Introducing Autonomous Self-Healing Function

“…By introducing sub-structures into smooth polydimethylsiloxane (PDMS) coatings, the SLIAS reached an ultra-low ice adhesion of 5.7 kPa. 32 In general, extremely low elastic moduli are required to achieve significant icephobicity. Yet, these extremely soft surfaces are not mechanically robust.…”

Interlaboratory Study of Ice Adhesion Using Different Techniques

“…The VST is very common due to its simple and economical set-up and performance, although the location of the force probe impacts the ice adhesion strength greatly [32], and the stress distribution may not be completely uniform [8,17,18]. The VST is commonly in use by several research groups [7,11,[32][33][34][35][36][37][38][39], and has been attempted as a standard for ice adhesion measurement utilizing only commercially available instruments [14]. When comparing reported ice adhesion strengths, it is also necessary to include the type of ice tested.…”

Liquid layer generators for excellent icephobicity at extremely low temperatures

“…of surfaces that can facilitate crack generation through stiffness inhomogeneity and deformation incompatibility as well as achieve super-low ice adhesion strength without the use of any surface additives. 18,19 Such MACI surfaces can be combined with other mechanisms to further reduce ice adhesion. Notably, other new strategies for anti-icing have emerged, particularly those that involve ice growth and patterns into the design of surface icephobicity.…”

“…24 The ice adhesion strength on dynamic anti-icing surfaces with an aqueous lubrication layer was reported to be B27 kPa, 24 which await optimization to achieve practical passive anti-icing application levels (lower than B12 kPa). 18,25 The icephobicity of the dynamic anti-icing surface critically relies on generating an interfacial aqueous layer. When this crucial interfacial liquid layer freezes at lower temperatures (for example, close to À60 1C), the ice adhesion strength can sharply increase to higher than 400 kPa.…”