Synthetic surfaces engineered to regulate phase transitions of matter and exercise control over its undesired accrual (liquid or solid) play a pivotal role in diverse industrial applications. Over the years, the design of repellant surfaces has transitioned from solely modifying the surface texture and chemistry to identifying novel material systems. In this study, selection criteria are established to identify bio‐friendly phase change materials (PCMs) from an extensive library of vegetable‐based/organic/essential oils that can thermally respond by harnessing the latent heat released during condensation and thereby delaying ice/frost formation in the very frigid ambient that is detrimental to its functionality. Concurrently, a comprehensive investigation is conducted to elucidate the relation between microscale heat transport phenomena during condensation and the resulting macroscopic effects (e.g., delayed droplet freezing) on various solidified PCMs as a function of their inherent thermo‐mechanical properties. In addition, to freeze protection, many properties that are responsive to the thermal reflex of the surface, such as the ability to dynamically tune optical transparency, moisture harvesting, ice shedding, and quick in‐field repairability, are achievable, resulting in the development of protective coatings capable of spanning a wide range of functionalities and thereby having a distinctive edge over conventional solutions.
Preventing water droplets from transitioning to ice is advantageous for numerous applications. It is demonstrated that the use of certain phase‐change materials, which are in liquid state under ambient conditions and have melting point higher than the freezing point of water, referred herein as phase‐switching liquids (PSLs), can impede condensation–frosting lasting up to 300 and 15 times longer in bulk and surface infused state, respectively, compared to conventional surfaces under identical environmental conditions. The freezing delay is primarily a consequence of the release of trapped latent heat due to condensation, but is also affected by the solidified PSL surface morphology and its miscibility in water. Regardless of surface chemistry, PSL‐infused textured surfaces exhibit low droplet adhesion when operated below the corresponding melting point of the solidified PSLs, engendering ice and frost repellency even on hydrophilic substrates. Additionally, solidified PSL surfaces display varying degrees of optical transparency, can repel a variety of liquids, and self‐heal upon physical damage.
more » « less- Award ID(s):
- 1644815
- NSF-PAR ID:
- 10444667
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials
- Volume:
- 31
- Issue:
- 17
- ISSN:
- 0935-9648
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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