Yongmei Zheng

Abstract:

Biological surfaces in nature (e.g., spider silk, cactus spine, beetle back, butterfly wing, lotus leaf, etc.) have inspired us to design functional materials and surfaces [1-5]. Inspired by the structures of spider silk for directional water collecting ability, a series of bioinspired gradient fibers has been designed by integrating fabrication methods and technologies, e.g., dip-coating, Rayleigh instability break-droplets, electrospinning, and wet-assembly, etc.. Thus, this allows roughness and curvature, gradient spindle-knots, a star-shape wettable pattern, etc. for droplet transport and harvesting. Inspired by cactus spines, the conical spines with periodic roughness or micro- and nanostructures can achieve high-efficiency condensed-droplet transport. Some dynamic gradient surfaces are also designed, e.g., photo-thermal organogel surfaces for control of droplet transport in various routes via light radiation, and magnetic-induced dynamic tilt-angle pillar array for driving of the droplet shedding-off in directions. The bioinspired gradient surfaces can be further designed to exhibit robust transport and control of droplets. These bioinspired gradient surfaces would be promising applications into anti-icing, liquid transport, anti-fogging/self-cleaning, water harvesting, etc.

[1] Zheng. Y. Bioinspired wettability surfaces: Development in micro- and nanostructures, Pan Stanford Publishing. 2015, 0-216.
[2] Zheng, Y. et al., Directional water collection on wetted spider silk, Nature 2010, 463, 640-463.
[3] Xu, T. et al., High-efficiency fog collector: water unidirectional transport on heterogeneous rough conical wires. ACS Nano 2016, 10, 10681-10688.
[4] C Gao, et al., Droplets Manipulated on Photothermal Organogel Surfaces. Adv. Funct. Mater. 2018, 1803072.
[5] Y. Lin, et al., Magnetically Induced Low Adhesive Direction of Nano/ Micropillar Arrays for Microdroplet Transport. Adv. Funct. Mater. 2018, 1800163.