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Name of experiment： The field wettability gradient drives the droplet to transport nondestructively over the superlubricated surface

Experiment content：

By introducing a field wettability gradient on a flat surface and printing a radial cross finger electrode array, the electric field can be pattered to generate a wettability gradient for directional droplet transport. Theoretical analysis and experimental results show that the droplet transport behavior can be evaluated by the dimensionless electric Bond constant, and the superlubricated surface can transport all kinds of droplet nondestructively.

Purpose of experiment：droplet transport mentioned in the experiment can be developed in heat transfer, pollution resistance, microfluidic and biochemical analysis applications.

Test equipment： 

electrode substrate, signal generator DG1032, high voltage amplifier ATA-2161, optical goniometer, optical microscope, PTFE film, high speed camera

Experimental process：

1. The experimental sample is prepared by covering the patterned electrode substrate with a hyperlubricating film (a-C in the figure below).

2. Connect the voltage signal output from the signal generator and the high voltage amplifier to the positive and negative electrodes ((d) in the figure below).

3. After DC or AC voltage is applied to the electrode substrate, the radial cross finger design of the electrode can generate electric field intensity gradient, which causes wettability gradient and realizes droplet transport.

Result of experiment：

Directional droplet transportation is realized, and related applications such as collection of organic microdroplets (a in the following figure), dust cleaning during droplet transportation (B in the following figure), and droplet transportation in oil phase environment (C in the following figure).