Biomimetics 2024, 9(12), 724; https://doi.org/10.3390/biomimetics9120724 (registering DOI) - 24 Nov 2024
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In nature, engineering technology and daily life, wetting phenomena are widespread and have essential roles and significance. Bionics is becoming increasingly important nowadays and exploring the mechanism that influences biomimetic surface microstructure on droplet wetting process and heat and mass transfer characteristics is
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In nature, engineering technology and daily life, wetting phenomena are widespread and have essential roles and significance. Bionics is becoming increasingly important nowadays and exploring the mechanism that influences biomimetic surface microstructure on droplet wetting process and heat and mass transfer characteristics is becoming more meaningful. In this paper, based on photolithography technology, SU-8 photoresist was used as raw material to prepare biomimetic surfaces with microstructures in various arrangements. The research results show that the wettability of biomimetic functional surfaces can be regulated by regulating the shape and arrangement of photoresist micro-pillars. At the same time, the effects of surface microstructure configuration and roughness on the heat and mass transfer processes within the droplets were also comprehensively studied. The results show that a biomimetic surface with cylindrical micro-pillars can effectively inhibit the evaporative cooling effect of the liquid–vapour interface. This effect becomes more evident with the increase in roughness, and the interface temperature difference can be reduced by up to 18%. Similarly, the biomimetic surface with cylindrical micro-pillars can also effectively promote the evaporation rate of sessile droplets, which can be increased by about 13%. In addition, the research also shows that regardless of the structure, substrate temperature changes will significantly impact the wetting phenomenon of the biomimetic surface. This study aims to guide the optimal design of biomimetic surfaces prepared based on photoresistance.
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Figure 1
Figure 1
<p>(<b>a</b>) Common bionic prototypes in the biomimetic surface design process (<b>b</b>) raw materials used for surface preparation; and (<b>c</b>) schematic diagram of the three-dimensional structure of photoresist micropillars.</p> Full article ">Figure 2
<p>Photoresist biomimetic surface production process.</p> Full article ">Figure 3
<p>Equipment and operation procedures for the evaporation experiment of sessile droplets on bionic surfaces.</p> Full article ">Figure 4
<p>Changes in contact angle and contact line of a 1.0 μL droplet on SS-1 and CS-3 surfaces at a substrate temperature of (<b>a</b>) 50 °C; (<b>b</b>) 60 °C; (<b>c</b>) 70 °C; (<b>d</b>) 80 °C.</p> Full article ">Figure 4 Cont.
<p>Changes in contact angle and contact line of a 1.0 μL droplet on SS-1 and CS-3 surfaces at a substrate temperature of (<b>a</b>) 50 °C; (<b>b</b>) 60 °C; (<b>c</b>) 70 °C; (<b>d</b>) 80 °C.</p> Full article ">Figure 5
<p>(<b>a</b>) Dimensionless height of a 1.0 μL droplet over time for different surfaces and substrate temperatures; (<b>b</b>) initial equilibrium contact angle of a 1.0 μL droplet on different surfaces and substrate temperatures.</p> Full article ">Figure 5 Cont.
<p>(<b>a</b>) Dimensionless height of a 1.0 μL droplet over time for different surfaces and substrate temperatures; (<b>b</b>) initial equilibrium contact angle of a 1.0 μL droplet on different surfaces and substrate temperatures.</p> Full article ">Figure 6
<p>Changes in contact angle and contact line of a 1.0 μL droplet on different surfaces at a substrate temperature of (<b>a</b>) 50 °C; (<b>b</b>) 60 °C; (<b>c</b>) 70 °C; (<b>d</b>) 80 °C.</p> Full article ">Figure 6 Cont.
<p>Changes in contact angle and contact line of a 1.0 μL droplet on different surfaces at a substrate temperature of (<b>a</b>) 50 °C; (<b>b</b>) 60 °C; (<b>c</b>) 70 °C; (<b>d</b>) 80 °C.</p> Full article ">Figure 7
<p>(<b>a</b>) The initial equilibrium contact angle of the droplet changes under different surface and substrate temperature conditions; (<b>b</b>) the initial adhesion work of the droplet changes under different surface and substrate temperature conditions.</p> Full article ">Figure 8
<p>Temperature distribution in the droplet liquid–vapour interface on the CS-3 and SS-3 surfaces at different periods when the substrate temperature is (<b>a</b>) 50 °C and (<b>b</b>) 80 °C.</p> Full article ">Figure 9
<p>The temperature distribution at the centre-line of the droplet’s liquid–vapour interface at different periods when the substrate temperature of the CS-3 surface is (<b>a</b>) 50 °C, (<b>c</b>) 60 °C, (<b>e</b>) 70 °C or (<b>g</b>) 80 °C; the temperature distribution at the centre line of the droplet’s liquid–vapour interface at different periods when the substrate temperature of the SS-3 surface is (<b>b</b>) 50 °C, (<b>d</b>) 60 °C, (<b>f</b>) 70 °C or (<b>h</b>) 80 °C.</p> Full article ">Figure 9 Cont.
<p>The temperature distribution at the centre-line of the droplet’s liquid–vapour interface at different periods when the substrate temperature of the CS-3 surface is (<b>a</b>) 50 °C, (<b>c</b>) 60 °C, (<b>e</b>) 70 °C or (<b>g</b>) 80 °C; the temperature distribution at the centre line of the droplet’s liquid–vapour interface at different periods when the substrate temperature of the SS-3 surface is (<b>b</b>) 50 °C, (<b>d</b>) 60 °C, (<b>f</b>) 70 °C or (<b>h</b>) 80 °C.</p> Full article ">Figure 10
<p>(<b>a</b>) Temperature difference at the droplet’s liquid–vapour interface in the initial state under different surface and substrate temperature conditions; (<b>b</b>) variation in the overall average evaporation rate of the droplet with the surface and substrate temperature.</p> Full article ">
<p>(<b>a</b>) Common bionic prototypes in the biomimetic surface design process (<b>b</b>) raw materials used for surface preparation; and (<b>c</b>) schematic diagram of the three-dimensional structure of photoresist micropillars.</p> Full article ">Figure 2
<p>Photoresist biomimetic surface production process.</p> Full article ">Figure 3
<p>Equipment and operation procedures for the evaporation experiment of sessile droplets on bionic surfaces.</p> Full article ">Figure 4
<p>Changes in contact angle and contact line of a 1.0 μL droplet on SS-1 and CS-3 surfaces at a substrate temperature of (<b>a</b>) 50 °C; (<b>b</b>) 60 °C; (<b>c</b>) 70 °C; (<b>d</b>) 80 °C.</p> Full article ">Figure 4 Cont.
<p>Changes in contact angle and contact line of a 1.0 μL droplet on SS-1 and CS-3 surfaces at a substrate temperature of (<b>a</b>) 50 °C; (<b>b</b>) 60 °C; (<b>c</b>) 70 °C; (<b>d</b>) 80 °C.</p> Full article ">Figure 5
<p>(<b>a</b>) Dimensionless height of a 1.0 μL droplet over time for different surfaces and substrate temperatures; (<b>b</b>) initial equilibrium contact angle of a 1.0 μL droplet on different surfaces and substrate temperatures.</p> Full article ">Figure 5 Cont.
<p>(<b>a</b>) Dimensionless height of a 1.0 μL droplet over time for different surfaces and substrate temperatures; (<b>b</b>) initial equilibrium contact angle of a 1.0 μL droplet on different surfaces and substrate temperatures.</p> Full article ">Figure 6
<p>Changes in contact angle and contact line of a 1.0 μL droplet on different surfaces at a substrate temperature of (<b>a</b>) 50 °C; (<b>b</b>) 60 °C; (<b>c</b>) 70 °C; (<b>d</b>) 80 °C.</p> Full article ">Figure 6 Cont.
<p>Changes in contact angle and contact line of a 1.0 μL droplet on different surfaces at a substrate temperature of (<b>a</b>) 50 °C; (<b>b</b>) 60 °C; (<b>c</b>) 70 °C; (<b>d</b>) 80 °C.</p> Full article ">Figure 7
<p>(<b>a</b>) The initial equilibrium contact angle of the droplet changes under different surface and substrate temperature conditions; (<b>b</b>) the initial adhesion work of the droplet changes under different surface and substrate temperature conditions.</p> Full article ">Figure 8
<p>Temperature distribution in the droplet liquid–vapour interface on the CS-3 and SS-3 surfaces at different periods when the substrate temperature is (<b>a</b>) 50 °C and (<b>b</b>) 80 °C.</p> Full article ">Figure 9
<p>The temperature distribution at the centre-line of the droplet’s liquid–vapour interface at different periods when the substrate temperature of the CS-3 surface is (<b>a</b>) 50 °C, (<b>c</b>) 60 °C, (<b>e</b>) 70 °C or (<b>g</b>) 80 °C; the temperature distribution at the centre line of the droplet’s liquid–vapour interface at different periods when the substrate temperature of the SS-3 surface is (<b>b</b>) 50 °C, (<b>d</b>) 60 °C, (<b>f</b>) 70 °C or (<b>h</b>) 80 °C.</p> Full article ">Figure 9 Cont.
<p>The temperature distribution at the centre-line of the droplet’s liquid–vapour interface at different periods when the substrate temperature of the CS-3 surface is (<b>a</b>) 50 °C, (<b>c</b>) 60 °C, (<b>e</b>) 70 °C or (<b>g</b>) 80 °C; the temperature distribution at the centre line of the droplet’s liquid–vapour interface at different periods when the substrate temperature of the SS-3 surface is (<b>b</b>) 50 °C, (<b>d</b>) 60 °C, (<b>f</b>) 70 °C or (<b>h</b>) 80 °C.</p> Full article ">Figure 10
<p>(<b>a</b>) Temperature difference at the droplet’s liquid–vapour interface in the initial state under different surface and substrate temperature conditions; (<b>b</b>) variation in the overall average evaporation rate of the droplet with the surface and substrate temperature.</p> Full article ">
