Surface‐Anchored Microgel‐Based Films as Anti‐Icing Coatings

Anti‐icing agents are highly interesting for a variety of applications such as the cryopreservation of cells, but also as coatings for outdoor technical appliances, which reduce wear and increase safety through ice‐phobic effects. In this work, microgels based on the biocompatible monomer N‐ vinylcaprolactam (VCL) and hydrophilic co‐monomer 1‐vinyl‐3‐methylimidazolium (VIM+) are applied as anti‐icing coatings. Furthermore, microgels additionally containing the monomer 3‐(acrylamido)phenylboronic acid (PBA‐AA) are synthesized. These microgels bind to surface hydroxy groups (e.g., on glass or plasma‐activated polymer films). Coating quality and enhanced durability are successfully demonstrated with different microscopy techniques. Tensile force measurements with a customized setup reveal an up to 90% lower ice adhesion force for polymer substrates coated with the synthesized microgels. The structure of the lubricating hydration layer and especially the presence of interfacial quasi‐liquid water with restricted mobility, eventually leading to a freezing point depression, are studied by differential scanning calorimetry (DSC) and nuclear magnetic resonance (NMR) spectroscopy.