Hydrophilic-hydrophobic heterogeneous patterned surface for enhancing dropwise condensation and preparation method

Abstract

The invention discloses a hydrophilic-hydrophobic heterogeneous patterned surface for enhancing dropwise condensation and a preparation method. The preparation method comprises the steps of sequentially polishing and degreasing the surface of a copper substrate to obtain a complete and clean copper surface; etching the copper surface by adopting a chemical etching method to obtain a super hydrophilic surface; coating the super hydrophilic surface with negative photoresist in a spinning manner; irradiating a pattern mask plate under UV light; arranging squares in array in super hydrophilic areas in the pattern mask plate, specifically, the distance between any two adjacent super hydrophilic areas is consistent; developing the copper surface by using a negative photoresist developer; rotationally plating a fluorinated polymer Cytop on the developed copper surface, and forming a superhydrophobic surface on the portion, uncovered by the photoresist, on the copper surface; and heating and curing the copper substrate by adopting a stripping process to obtain the super-hydrophilic / super-hydrophobic patterned combined surface. The hydrophilic-hydrophobic heterogeneous patterned surface prepared by the preparation method can enhance the dropwise condensation efficiency and improve the condensation heat transfer coefficient of the surface.

Description

technical field [0001] The invention belongs to the field of metal surface treatment, and in particular relates to a hydrophilic-hydrophobic heterogeneous patterned surface with enhanced droplet condensation and a preparation method. Background technique [0002] Steam condensation widely exists in industrial fields such as thermal power generation, industrial waste heat utilization, and building heating and cooling. Generally, according to the wettability of the condensing surface, the condensation mode can be divided into droplet condensation and film condensation. Droplet condensation occurs on a non-wet surface, which can produce better condensation heat transfer performance, and its condensation heat transfer coefficient is 5-10 times that of film condensation. Although the condensation effect of film condensation is poor, the thermal resistance of droplet nucleation is small and the nucleation is rapid. A surface with a droplet static contact angle greater than 150° ...

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Problems solved by technology

Patent CN109732195A discloses a method for preparing a superhydrophobic-superhydrophilic surface on a titanium alloy using pulsed laser technology. The arrangement of hydrophilic regions and superhydrophobic regions is staggered and disorderly, and the shedding diameter and merging frequency of condensate droplets cannot be well regulated, and the cost of laser processing and manufacturing is relatively high

Patent CN111069001A invented a bionic hydrophobic-hydrophilic surface material, a micro-nano composite composite surface formed by constructing nano-protrusions on a composite surface with hydrophilic micro-protrusions interspersed with hydrophilic-hydrophobic regions material, the static contact angle of droplets on the composite hydrophilic-hydrophobic surface is 90-130°, but the composite surface is a non-superhydrophilic surface and a non-superhydrophobic surface, which fails to give full play to the low composition of the superhydrophilic surface. Advantages of nuclear thermal resistance and high condensation heat transfer coefficient on superhydrophobic surfaces

Patent CN110255492A discloses a method of using laser processing technology to make a super-hydrophobic and super-hydrophilic area distribution surface on a silicon substrate. This method needs to combine chemical modification, laser ablation processing and mask plate UV irradiation, and the processing is difficult. , the cost is high, and the substrate is non-metallic silicon wafer material, it is difficult to use in engineering heat transfer fields such as condensation heat exchangers and high-temperature distillers

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