Temperature-gradient-induced enhanced fog collection on polymer brush surfaces

Since the global water shortage, fog collection based on functional materials and surfaces has become one of the most potential ways to relieve the crisis. However, further improving the water collection efficiency through elaborate designs of material structures still encounters a bottleneck. Here, we present a temperature gradientinduced strategy for enhancing water collection from fog. Such a temperature modulation generates increases in the fog collection efficiency and surface-refreshing frequency by 25% and 217%, respectively. Scattering measurements show that the movement velocity of fog particles near cooling surfaces is increased by approximately 150%. Based on the theory of heat transfer and thermophoresis, the temperature field acting on fog particles is analyzed, deducing that the enhanced fog-collection performance results from thermophoretic forces generated by temperature gradients. This work offers a new approach for designing next-generation fog-collection devices and manipulating particle motions.