Study on Nonfluorinated Preparation and Properties of Superhydrophobic Surface

The preparation of a superhydrophobic surface on metal can improve the self-cleaning, antifouling, and anti-bacterial properties of the surface. At present, the superhydrophobicity of the sample surface is mostly obtained by modifying the rough surface with fluorine-containing modifiers, which is unfavorable to the environment. Therefore, developing superhydrophobic surfaces without environmental pollution has become a research hotspot. Based on laser etching technology, the rough surface with a micro-nano dual-scale structure was prepared on aluminum alloy, and then a green and natural saturated fatty acid - myristic acid was used to modify the rough surface. Contact angle measuring instrument, depth of field microscope, scanning electron microscope and Fourier transform infrared spectrometer were used to characterize the wettability, surface morphology, and chemical composition of the modified rough surface (S1). Self-cleaning, anti-contamination, antibacterial, mechanical durability, and thermal stability of the S1 surface were tested experimentally. The wetting of droplets on hydrophobic surface was simulated by using COMSOL Multiphysics software, and a computational model was established to compare different functional structures, so as to understand the influence of parameters on the enhancement of hydrophobic properties of material surface. The results showed that the static contact angle (WCA) of the surface modified by myristic acid reached 152.3 degrees, and the hydrophobic index was -0.808, and the WCA value first increased and then decreased with the change of modification time and concentration. With the increase of myristic acid concentration, the peak value of the contact angle WCA of S1 was negatively correlated with modification time. The self-cleaning rate, anti-stain rate, and antibacterial rate of S1 were 91.4%, 83.6% and 88.4%, respectively, showing excellent self-cleaning, anti-stain, and antibacterial ability. In the mechanical durability test, the S1 surface can resist at least 50 times tape peeling, 30 times steel wool friction and wear, the and 180 g sand falling impact test still keeps superhydrophobic. In the thermal stability test, the S1 surface remains superhydrophobic after heat treatment at 100-200 degrees C for 30 h. In this study, the multifunctional superhydrophobic surface was obtained on aluminum alloy by laser etching technology combined with a green fluorine-free modifier, which provided some meaningful ideas and references for the green preparation of superhydrophobic surfaces and the application and development of superhydrophobic surfaces in biomedical metals.