Fabrication of Superhydrophobic Stainless Steel Nozzles by Femtosecond Laser Micro-/Nano-Texturing
Tatsuhiko Aizawa*,, Tadahiko Inohara**, and Kenji Wasa***
*Surface Engineering Design Laboratory
3-15-10 Minami-rokugo, Ota, Tokyo 144-0045, Japan
**L.P.S. Works Co., Ltd., Tokyo, Japan
***MicroTeX Labs, LLC, Tokyo, Japan
A dispensing nozzle is an essential mechanical element in inkjet, dot, and bioprinting. To improve the printing resolution, the inner diameter of the nozzle outlet must be as small as possible. A droplet dispensed through a hydrophilic stainless steel outlet expands on the whole outlet surface and along the side surface of the nozzle. This issue can be solved by physical surface modifications. In the present paper, a femtosecond laser micro-/nano-texturing method was developed to transform the originally hydrophilic stainless steel surface of a nozzle to a hydrophobic or superhydrophobic one. First, an AISI304 plate was used to demonstrate experimentally that, on its surface, the tailored micro-/nano-patterns were reproduced as micro-/nano-textures, making the surface superhydrophobic. Second, the technique was applied to the physical surface modification of an AISI304 stainless steel nozzle outlet by optimizing the femtosecond laser machining conditions. A high-speed camera was used to take a snapshot of the dispensed droplet from the surface-modified outlet. Finally, a line-printing experiment was performed to characterize the dispensing behavior of the stainless steel nozzles with and without physical surface modification.
-  TecDia, Catalogue of nozzles, 2019.
-  U. Resigen et al., “Multi-dimensional line dispensing of unfilled adhesives,” Microsystem Technologies, Vol.14, No.12, pp. 1895-1901, 2008.
-  https://www.micro-mechanics.com/dispensing-dnozzle-groove-dn [Accessed July 21, 2019].
-  https://www.ihs-lub.com/en/ [Accessed July 21, 2019].
-  K. Nakane, “How to form the hydrophobic and super-hydrophobic surfaces in industries,” Industrial Mater., Vol.44, pp. 26-30, 1996.
-  B. Kobrin, T. Zhang, and J. Chinn, “Choice of precursors in vapor-phase Surface modification,” Proc. 209th Electrochemical Society Meeting, pp. 117-120, 2006.
-  Y. Chen, B. He, J. Lee, and N. A. Patankar, “Anisotropy in the wetting of rough surfaces,” J. Colloid and Interface Science, Vol.281, No.2, pp. 458-464, 2005.
-  Y. T. Cheng and D. E. Rodak, “Is the lotus leaf super-hydrophobic?,” Applied Physics Letters, Vol.86, pp. 144101-144109, 2005.
-  D. E. Packham, “Surface energy, surface topography and adhesion,” Int. J. of Adhesion and Adhesives, Vol.23, pp. 437-448, 2003.
-  S. Hoehm, A. Rosenfeld, J. Krueger, and J. Bonse, “Femtosecond laser-induced periodic surface structures on silica,” J. Applied Physics, Vol.1121, pp. 0149010-0149019, 2012.
-  L. Orazi, L. Gnilitskyi, and A. P. Serro, “Laser nanopatterning for wettability applications,” J. Micro-and Nano-Manufacturing, Vol.5, pp. 021008-1-021008-8, 2017.
-  A. M. Kietziga, M. N. Mirvakilia, S. Kamalb, P. Englezosa, and S. G. Hatzikiriakos, “Laser-patterned super-hydrophobic pure metallic substrates: cassie to wenzel wetting transitions,” J. Adhesion Science and Technology, Vol.25, pp. 2789-2809, 2011.
-  P. Gečys, A. Vinčiūnas, M. Gedvilas, A. Kasparaitis, R. Lazdinas, and G. Račiukaitis, “Ripple formation by femtosecond laser pulses for enhanced absorptance of stainless steel,” JLMN-J. Laser Micro/Nanoengineering, Vol.10, pp. 129-133, 2015.
-  D. H. Kam, S. Bhattacharya, and J. Mazumder, “Control of wetting properties of an AISI316 stainless steel surface by femtosecond laser-induced surface modification,” J. Micromechanics and Microengineering, Vol.22, pp. 105019-1-105019-6, 2012.
-  T. Aizawa and T. Inohara, “Pico- and femto-second laser micromachining for surface texturing,” Z. Stanimirović and I. Stanimirović (Eds.), “Micromachining,” IntechOpen, 2019.
-  T. Aizawa, T. Hasegawa, and T. Inohara, “Surface geometry control of stainless steels by femtosecond laser nano-/micro-texturing toward super-hydrophilicity and super-hydrophobicity,” Proc. 12th AFGS (August 12th, Kunming, China), pp. 71-78, 2019.
-  T. Hasegawa, T. Aizawa, T. Inohara, K. Wasa, and M. Anzai, “Hot mold stamping of optical plastics and glasses with transcription of super-hydrophobic surfaces,” Procedia Manufacturing, Vol.15, pp. 1437-1444, 2019.
-  T. Hasegawa, T. Aizawa, T. Inohara, and S. Yoshihara, “Mold-stamping of optical glasses by micro/nano-textured die to transcript the hydrophobicity,” J. JSTP, Vol.60, pp. 23-27, 2019.
-  T. Aizawa, T. Inohara, and K. Wasa, “Femtosecond laser micro/nano-texturing of stainless steels for surface property control,” Micromachines, Vol.10, No.8, E512, 2019,
-  T. Kawase, “Superhydrophobic surface,” SEN’I GAKKAI, Vol.65, pp. 200-207, 2009.
-  J. Li, Q. Du, and C. Sun, “An improved box-counting method for image fractal dimension estimation,” Pattern Recognition, Vol.42, No.11, pp. 2460-2469, 2009.
-  T. Aizawa and K. Wasa, “Plasma nitriding of inner surfaces in the mini- and micro-nozzles for joining,” Proc. 4M/IWMF-2016, pp. 145-148, 2016.
-  T. Aizawa, “Low temperature plasma nitriding of austenitic stainless steels,” Z. Duriagina (Ed.), “Stainless Steels and Alloys,” IntecOpen, pp. 31-50, 2018.
-  T. Aizawa and K. Wasa, “Low temperature plasma nitriding of inner surfaces in the stainless steel mini-/micro-pipes and nozzles for industries,” Micromachines, Vol.7, No.4, pp. 1-10, 2016.