April 2021
Vol 7, Issue 18

About The Cover

Cover image expansion

ONLINE COVER Crystal fouling, in which precipitants accumulate on materials and cause damage over time, leads to pervasive issues in industrial processes such as water treatment and thermoelectric power production. While studying this effect, McBride et al. discovered a phenomenon in which crystals self-eject from heated materials with nano-textured, water-repelling surfaces during saline water drop evaporation. Since these "crystal critters" make very minimal contact with the substrate, they prevent crystal fouling. The researchers determined that this effect occurs due to a combination of confinement effects within the nanotexture of the substrate and water vaporizing at the hot surface. Uncovering this critter effect may have important implications for solving the problem of spray cooling heat exchanger fouling. Additionally, insights from these findings could be applied to advance drop-based fluidic machines and self-propulsion. [CREDIT: JOHN LAKE AND SAMANTHA MCBRIDE ET. AL/SCIENCE ADVANCES]