| Condensation is a common phenomenon in daily life and industrial production.The water film formed by condensation not only affects the heat exchange efficiency of the surface,but also reduces the recovery effect of condensate droplets.In order to improve the water collecting efficiency in industrial field,inspired by spider silk,cactus,desert beetle and other special hybrid wettability surfaces in nature,this paper carried out the research on bionic hybrid wettability surfaces.Based on the characteristics of high nucleation rate of droplet in hydrophilic region and fast moving speed of droplet leaving the surface in superhydrophobic region,the amount of condensation on the surface was increased,and the effect of collecting water by droplet condensation on the surface was enhanced.The main research contents and results are as follows:Four micro-wedge silicon column arrays of different sizes and gaps were processed by photolithography,firstly coated with nano-silica superhydrophobic coating to obtain a superhydrophobic coating,then the top coating of the silicon column was removed to expose the silicon substrate,and silicon The superhydrophobic coating at the bottom of the column is retained to obtain a hydrophobic-superhydrophobic patterned hybrid wettability surface with the surface contact angle of 150° or more and the roll angle below 10°.The condensation test shows that the nucleation rate of the surface of the pattern with small wedge size and large gap is high,the droplets with diameter less than 30?m are close to 90%,and the droplets with diameter larger than 50?m are only 3%;the results of water collection test show that the pattern The total mass of condensed droplets on the surface is increased by more than 10 times compared to a single superhydrophobic surface.Hydrophilic modification of the exposed top of the silicon column to obtain a patterned hydrophilicsuperhydrophobic surface.The surface water condensation efficiency of the same pattern surface was improved compared with the hydrophobic-superhydrophobic surface,and the nucleation rate of the surface of the sample was increased.The droplet desorption cycle is fast,and the surface condensation condensation condensation effect is promoted,and the surface condensation condensation effect can be effectively regulated.Based on the research of nano-silica superhydrophobic coatings,hybrid wettability coatings were prepared by particle hybridization technology.The particle hybrid wettability coating was prepared by spraying or immersing pulling process.The effects of particle type,particle ratio,particle size and coating thickness on surface condensation characteristics and condensation water collection performance were compared and analyzed.The experiment shows that after collecting water for 5h at room temperature,the hybrid wettability coating prepared by hybridization of hydrophilic SiC particles can be selected.The surface dew condensation water collection efficiency can reach 1600g/m2?h,which is higher than nano-oxidation.The silicon superhydrophobic coating is improved by 67%,and the water collection efficiency of the untreated hydrophilic surface is increased by 81%,which has an excellent enhanced condensation condensation water collection effect.Based on the study of hybrid wettability surface with hydrophilic particle hybridization,the PP primer was used to pre-roughen the substrate,and the organic resin/coating was used as the reinforcement to prepare the hybrid wettability coating surface,with a contact angle of approximately 158° and a rolling angle of less than 5°.After testing,the composite resin prepared with FEVE and acrylic acid ratio of 1:1 as the reinforcement has good wear resistance,and can maintain excellent superhydrophobic property after 30 cycles of finger rubbing.The surface base film adhesion is 3-The level 4 is increased to zero level;at the same time,the prepared coating still has excellent droplet condensing and dew condensation water collecting conditions under the condition of 99% relative humidity. |
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