Preparing method for aluminum foil gradient wettability surface with nano coarse structure

Abstract

The invention relates to a preparing method for aluminum foil gradient wettability surface with a nano coarse structure, which includes the steps as follows: stripped aluminum foil with the length of 5 to 20cm is ultrasonically cleaned, dried and immersed in NaOH water solution to be treated; phosphoric acid and glycerol mixed water solution is taken as electrolyte to perform anodic oxidation at a room temperature and under a constant current density mode, so as to achieve the nano coarse surface of the aluminum foil; the aluminum foil is tilted in an open empty container with the nano coarse surface facing upward, and under the condition of room temperature, the fluoroalkyl silane ethanol solution with the volume fraction of 0.14 to 0.24% is dripped in with the uniform velocity of 2.5 to 7.5ml / min within the time of 15 to 25min; and the aluminum foil taken out of the container is placed in a drying oven of 60 degrees C for 15min, then the gradient wettability of the nano coarse surface of the aluminum foil can be achieved, the gradient covering length is 5 to 15cm, the contact angle can be uniformly reduced from 155 degrees to lower than 5 degrees, and the progressive reducing amplitude is 10 to 30 degree / cm.

Description

technical field [0001] The invention relates to a preparation method of an aluminum foil gradient wettability surface with a nano-rough structure. Background technique [0002] Gradient wetting surfaces (continuous changes in wettability) have broad application prospects in the fields of protein adsorption, cell adhesion, microfluidics, and enhanced heat transfer. The directional movement of water droplets on a gradient wetting surface was first predicted by Greenspan in 1978 [H.P.Greenspan, J.Fluid Mech., 1978,84,125]. It was not until 1992 that Chaudhury and Whitesides used the silane gas phase diffusion method to obtain a gradual chemical modification within a length of 1cm [M.K.Chaudhury, G.M.Whitesides.Science.1992,256,1539], and prepared a wettability of 97°-25° Gradient, and realized the directional movement of water droplets to the hydrophilic end, which verified the above prediction. Since then, wettability gradient surfaces on substrates such as silicon, glass, a...

AI Technical Summary

Problems solved by technology

In addition, there are also wettability gradient technology, which is currently mainly used on the surface of gold and silicon wafers. The process is more complicated, difficult to control, and the cost is higher. The gradient coverage length is relatively small, generally less than 4cm.

At the same time, most of the drugs used are polluting, not environmentally friendly, and unsafe

Low-cost fabrication techniques for gradient-wetting surfaces of common metals are rarely reported

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