Dalian University of Technology

Jinlong Song

Xin Liu

Liu Huang

Yuwen Sun

Xuyue Wang

Changlin Zhao

Mingqian Gao

A superhydrophobic hemispherical array which can realize droplet pancake bouncing phenomenon is provided. The superhydrophobic hemispherical array shows an arc-shape structure which is narrow at the top and wide at the bottom, where a is the angle that substrate-gas interface goes across the gas and reaches substrate-hemisphere interface, d refers to the diameter of the contact area between hemispherical structure and substrate, s represents the space between two adjoining hemispheres, h denotes the vertical height from the top of hemisphere to substrate surface, and 70&#xb0;&#x2264;a&#x2264;90&#xb0;, 900 &#x3bc;m&#x2264;d &#x2264;1700 &#x3bc;m, s&#x2264;550 &#x3bc;m, 600 &#x3bc;m&#x2264;h&#x2264;1100 &#x3bc;m, respectively. The superhydrophobic hemispherical array has a water contact angle larger than 150&#xb0; and roll-off angle lower than 10&#xb0;.

Superhydrophobic hemispherical array which can realize droplet pancake bouncing phenomenon

A thermal extrusion method to fabricate large-dimension superhydrophobic cylinder pillar arrays with droplet pancake bouncing phenomenon. Preparing thermal extrusion mold: the through-hole arrays with 0.8&#x2dc;1.25 mm diameter, 0.25 mm interval space and 0.6&#x2dc;1.0 mm height are first obtained on metals, and are then polished, rinsed and dried. Thermal extrusion: polymer materials are first thermally extruded on the obtained mold and cooled to room temperature. Demold: excess polymer materials flowing from the through hole are cut off and then the polymer cylinder pillar arrays are lifted off from the mold. Superhydrophobic treatment: the whole polymer sample is treated using mixed liquid spray consisting of titanium oxide nanoparticles dispersed in fluoroalkylsilane ethanol solution, and the superhydrophobic cylinder pillar arrays are obtained. The method is easy to operate, low-cost, recyclable, effective for different polymer materials, and can obtain cylinder pillar arrays with large dimensions, which can realize efficient large-area and industrial fabrication of the droplet pancake bouncing surfaces.

Thermal extrusion method to fabricate large-dimension superhydrophobic cylinder pillar arrays with droplet pancake bouncing phenomenon

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Dalian, China

Jinlong Song