CC BY
11LP-I-11
Nanosecond laser treatment and fluoropolymer deposition for control of silicon surface wettability
S. Starinskiy1,2, A. Safonov1, E. Gatapova1, N. Miskiv1, E. Bochkareva1, V. Sulyeva3, A. Rodionov1,2, Y. Shukhov1, A. Bulgakov1,4
institute of Thermophysics, Sb RAS, Novosibirsk, Russian Federation
2Novosibirsk State University, Physical Department, Novosibirsk, Russian Federation
3Institute of Inorganic Chemistry, Sb RAS, Novosibirsk, Russian Federation
4HiLASE Centre, Institute of Physics of the Czech Academy of Sciences, Dolni Brezany, Czech
Republic
The extreme wettability surfaces (superhydrophilic and superhydrophobic) is very perspective for different application in textile industry, creating surfaces with anti corrosion and self-cleaning property, in separation filters, antifogging materials, heat exchangers, biosensors and biochips, etc. Recently, there has been a particular interest in material with a sharp boundary between superhydrophilicity and superhydrophobicity due to the particular behavior of the liquid along the contact line on such so-called biphilic materials. There are two main approaches to achieve extreme surface wettability. The first one suggests changing the surface texture (roughness) while the second one is based on varying the surface free energy by its functionalization. In this work, we combine this approaches by laser treatment of silicon and following HW CVD of fluoropolymer. We found a narrow range of conditions of nanosecond ablation by IR laser of silicon in which the two-level morphology of the surface is formed. It are pores at the nanoscale and self-organized periodic hills structure at the microscale. The surface enrichment with oxygen is observed in addition to changes in morphology, that leads to supehydrophilicity of silicon. The smooth transition from supehydrophilicity to superhydrophobicity achieved by gradually deposition of fluoropolymer. Thus, a silicon with an arbitrary apparent contact angle within the range from ~0° to 170° can be obtained. The wettability properties were controlled by varying the thickness of fluoropolymer coating. It is demonstrated further functionalization of obtained materials by local removal of fluoropolymer by laser in the mode of preservation of superhydrophilic properties of silicon. The possibility of using the obtained biphilic samples in the problem of droplet evaporation is considered.
The work was supported by the Russian Science Foundation (project No. 18-79-10119).
