Spatial control of condensation and desublimation using ice nucleating proteins

Abstract

On a subfreezing surface, nucleating embryos usually form as supercooled condensate that later freezes into ice, as opposed to desublimation. Ice nucleating proteins (INPs) have been widely used to quickly freeze existing supercooled water; however, nobody has studied how they might affect the initial mode of embryo formation. We show that INPs deposited on a substrate can switch the mode of embryo nucleation to desublimation, rather than supercooled condensation, beneath a critical temperature. By patterning a hydrophobic surface with an array of hydrophilic stripes, the INPs can be selectively deposited by evaporating water that exclusively spreads along the hydrophilic regions. The resulting array of desublimating ice stripes created dry zones free of condensation or frost in the intermediate areas, as the hygroscopic ice stripes served as overlapping humidity sinks.

Inhibiting Condensation Freezing on Patterned Polyelectrolyte Coatings

“…Ice formation in humid environments usually goes through condensation but not via direct desublimation as predicted by the Ostwald’s rule of stages more than 100 years ago. Therefore, inhibiting condensation freezing can provide an effective strategy for anti-icing applications on various surfaces. , The efficiency of this anti-icing strategy was fully demonstrated by recent reports, that is, suppression of frost formation via preventing condensation achieved by introducing nanoengineered humidity sinks or micropatterned ice stripes. − Condensation freezing inhibition coatings that can be applied on different surfaces remain a challenge. − Herein, we report the inhibition of condensation freezing on patterned polyelectrolyte surfaces. We show that ice stripes can exclusively and spontaneously form atop the polyelectrolyte patterns, which leads to a sudden release of latent heat. − As a result, surrounding condensed water droplets evaporate, leading to a region of ice free (RIF).…”

Suppressing Condensation Frosting Using an Out-of-Plane Dry Zone

“…57,65 By promoting an array of periodic ice features across a surface, overlapping dry zones completely prevent the formation of condensation or frost in the intermediate surface areas. These ice patterns can be templated by using chemical patterns, 57 physical patterns, 57,60 ice nucleating proteins, 58 or polyeletrolytes. 61 To date, the hygroscopic ice patterns were always placed directly on the same substrate where the antifrosting functionality was desired.…”

“…In short, the above techniques for combating frost require active input, break down after a finite time, and/or advanced and potentially fragile surface coatings. Motivated to bypass these constraints, several recent reports have demonstrated passive antifrosting using sacrificial ice patterns in place of antifreeze chemicals. − It is well-known by atmospheric scientists that ice is a naturally hygroscopic material . This can be visualized by freezing a droplet on a substrate, bringing the surface beneath the dew point, and observing an annular dry zone of inhibited condensation frosting form about the perimeter of the ice. , Using ice as the hygroscopic material is uniquely attractive in two ways: it requires no synthetic chemicals, and the hygroscopicity of the ice never gets diluted as it harvests water vapor. , By promoting an array of periodic ice features across a surface, overlapping dry zones completely prevent the formation of condensation or frost in the intermediate surface areas.…”

“…This can be visualized by freezing a droplet on a substrate, bringing the surface beneath the dew point, and observing an annular dry zone of inhibited condensation frosting form about the perimeter of the ice. , Using ice as the hygroscopic material is uniquely attractive in two ways: it requires no synthetic chemicals, and the hygroscopicity of the ice never gets diluted as it harvests water vapor. , By promoting an array of periodic ice features across a surface, overlapping dry zones completely prevent the formation of condensation or frost in the intermediate surface areas. These ice patterns can be templated by using chemical patterns, physical patterns, , ice nucleating proteins, or polyeletrolytes …”

Bioinspired Anti-Icing Hydrogel Enabled by Ice-Nucleating Protein

“…20,21 Integrating these active INPs into icephobic materials will provide promising anti-icing strategies for scientific research and enable widespread anti-icing applications in different conditions. 22,23 Here, we report an anti-icing coating of patterned hydrogel-encapsulated INP (PHINP) based on a simple projection printing method. 24 INPs will trigger freezing of the freezable interfacial water inside the hydrogel preferentially at high subzero temperatures, generating patterned frozen PHINP coatings exclusively on substrates.…”