Frost prevention through Nanoengineered Integral Humidity Sink Effect

Prevention of ice and frost formation is important for transportation and power generation industries. While many passive coatings that are supposed to achieve this goal have been proposed, most loose functionality in frosting conditions. In this talk, we will discuss how responsive two-layer antifreeze infused coatings can address this issue. These bioinspired bi-layered coatings have an inner superhydrophilic ``dermis'' infused with antifreeze and an outer permeable superhydrophobic ``epidermis'' [1]. Besides outperforming any passive coatings in conditions that lead to glaze and rime formation (with major antifreeze use reduction), our coatings also provide intriguingly long condensation onset delay. This result stems from the integral humidity sink effect where in the periodically exposed hygroscopic liquid depresses vapor concentration below saturation level required for nucleation to occur on the exterior surface [2]. We will discuss basic scaling laws that govern this process and how the exterior surface porosity can be engineered to optimize the anti-frosting capability of the bi-layer coating [3].

[1] Sun et al. Adv. Mater. Inter. 2015.

[2] Sun et al. Langmuir, 2016.

[3] Sun et al. ACS Nano, 2017.