대한기계학회논문집B (Transactions of the Korean Society of Mechanical Engineers B)

  • 제41권8호
  • /
  • Pages.531-536
  • /
  • 2017
  • /
  • 1226-4881(pISSN)
  • /
  • 2288-5324(eISSN)
대한기계학회 (The Korean Society of Mechanical Engineers)
권호 표지
DOI QR코드

DOI QR Code

방사광 X-선 영상법을 활용한 마이크로/나노 구조 표면에서의 액체 퍼짐 가시화 연구

A Visualization Study of Liquid Spreading on Micro/nano Textured Surfaces with Synchrotron X-ray Imaging

  • 곽호재 (포항공과대학교 기계공학과) ;
  • 유동인 (한국원자력연구원 해양원전개발센터) ;
  • 도승우 (포항공과대학교 첨단원자력공학부) ;
  • 박현선 (포항공과대학교 첨단원자력공학부) ;
  • 김무환 (포항공과대학교 기계공학과)
  • Kwak, Ho Jae (Dept. of Mechanical Engineering, POSTECH) ;
  • Yu, Dong In (Maritime Reactor Development Center, Korea Atomic Energy Research Institute) ;
  • Doh, Seungwoo (Division of Advanced Nuclear Engineering, POSTECH) ;
  • Park, Hyun Sun (Division of Advanced Nuclear Engineering, POSTECH) ;
  • Kim, Moo Hwan (Dept. of Mechanical Engineering, POSTECH)
  • 투고 : 2017.02.08
  • 심사 : 2017.06.01
  • 발행 : 2017.08.01
PDF 다운로드
⟨ 이전 논문 다음 논문 ⟩

초록

최근들어 고체 표면의 젖음성을 향상시키기 위해 표면에 나노/마이크로 기술을 적용하는 연구가 진행되고 있다. 이러한 연구를 통하여 나노 구조가 표면 젖음성을 향상 시킬 수 있고, 액체 퍼짐은 실 모세관(Capillary wicking)에 의해 형성된다는 것을 확인하였다. 그러나 대부분의 연구는 나노 구조의 작은 스케일때문에 분석하는데 어려움이 있어서 퍼짐현상을 정성적으로 분석하고 있다. 본 연구에서는 마이크로/나노/마이크로-나노 구조를 갖는 실리콘 표면에서의 액적 계면 거동을 정량적으로 분석하였으며, 계면의 거동은 방사광 X선 영상법으로 직접 측면가시화를 진행하였다. 그 결과 모든 구조 표면에서 퍼짐 현상이 발생하였고, 액체 계면의 거동이 서로 다르게 나타났다. 마이크로구조의 경우 일정한 액막 두께를 유지하며 퍼졌고, 나노구조는 완만한 경사를 갖는 것으로 나타났다. 마이크로-나노 구조의 경우 두 가지가 결합된 형태의 퍼짐현상을 보였다. 또한 액체의 퍼짐은 마이크로-나노 구조에서 가장 증진됨을 확인하였다.

Nano/micro technology is currently applied to improve solid surface wettability, with recent research studies indicating that nanostructures can improve surface wettability in the hydrophilic direction, and liquid spreading (propagation) is generated by capillary wicking. The majority of the existing research involves qualitative analysis of the spreading phenomena, owing to the difficulty in conducting small-scale analysis (nanostructures). In this study, the droplet interfacial behavior on silicon surfaces with micro/nano/micro-nano structures is experimentally investigated. The interfacial behavior is directly visualized using synchrotron X-ray imaging (side view). The spreading phenomena occur on structured surfaces, and the liquid interface behaviors on the surfaces differ. The liquid film thickness is uniform during spreading on the microstructured surface, but not on the nano case which shows a gentle slope. These combined spreading shapes were observed on a micro-nano structured surface, and liquid propagation was enhanced when the micro- and nano-structures are combined.

키워드

참고문헌

  1. Young, T., 1805, "Analysis of Interfacial Forces, London.", Philos Trans Roy Soc., 95, pp. 65-73. https://doi.org/10.1098/rstl.1805.0005
  2. Wenzel, R.N., 1936, "Resistance of Solid Surfaces to Wetting by Water," Industrial and Engineering Chemistry, Vol. 28, No. 8, pp. 988-993. https://doi.org/10.1021/ie50320a024
  3. Cassie, A. and Baxter, S., 1944, "Wettability of Porous Surfaces," Transaction of the Faraday Society, Vol. 30, pp. 546-551.
  4. Dettre, R. and Johnson, R., 1963, "Study of an Idealized Heterogeneous Surface," The Journal of Physical Chemistry, 107, 43, pp. 1744-1750.
  5. Kim, D.H., Kim, J.W. and Hwang, W.B., 2006, "Prediction of Contact Angle on a Microline Patterened Surface," Surface Science, Vol. 600, No. 22, pp. 301-304. https://doi.org/10.1016/j.susc.2006.09.026
  6. Marmur, A., 2008, "From Hygrophilic to Superhygrophobic: Theoretical Conditions for Making High-contact-angle Surfaces from Low-contact-angle Materials," Langmuir, 24, 14, pp. 7573-7579. https://doi.org/10.1021/la800304r
  7. Nakajima, A., Hashitomo, K., Watanabe, T., Taki, K., Yamaguchi, G. and Fujishima, A., 2000, "Transparent Superhydrophobic Thin Films with Self-Cleaning Properties," Langmuir, Vol. 16, No. 17, pp. 7044-7047. https://doi.org/10.1021/la000155k
  8. Furstner, R., Barthlott, W., Neinhuis, C. and Walzel, P., 2005, "Wetting and Self-Cleaning Properties of Artificial Superhydrophobic Surfaces," Langmuir, Vol. 21, No. 3, pp. 956-961. https://doi.org/10.1021/la0401011
  9. Hocker, H., 2002, "Plasma Treatment of Textile Fibers," Pure Appl. Chem. Vol. 74, No. 3, pp. 423-427. https://doi.org/10.1351/pac200274030423
  10. Choi, C.-H. and Kim, C.-J., 2006, "Large Slip of Aqueous Liquid Flow over a Nonoengineered Superhydrophobic Surface," Phys. Rev. Lett., Vol. 96, No. 6, pp. 066001.1-4.
  11. Marmur, A., 2005, "Underwater Superhydrophobicity," Langmuir, Vol. 22, No. 4, pp. 1400-. https://doi.org/10.1021/la052802j
  12. Genzer, J. and Marmur, A., 2008, "Biological and Synthetic Self-cleaning Surfaces," MRS Bull. Vol. 33, No. 8, pp. 742-746. https://doi.org/10.1557/mrs2008.159
  13. Boreyko, J. B. and Chen, C.-H., 2009, "Self- Propelled Dropwise Condensate on Superhydrophobic Surfaces," Phys. Rev. Lett., Vol. 103, No. 18, pp. 184501.1-4.
  14. Ahn, H. S., Jo, H. J., Kang, S. H. and Kim, M. H., 2011, "Effect of Liquid Spreading due to Nano/micro Structures on the Critical Heat Flux during Pool Boiling," Appl. Phys. Lett., Vol. 98, No. 7, pp. 071908.1-3.
  15. Chu, K.-H., Enright, R. and Wang, E. N., 2012, "Structured Surfaces for Enhanced Pool Boiling Heat Transfer," Appl. Phys. Lett., Vol. 100, No. 24, pp. 241603.1-4.
  16. Chu, K.-H., Joung, Y. S., Enright, R., Buie, C. R. and Wang, E. N., 2013, "Hierarchically Structured Surfaces for Boiling Critical Heat Flux Enhancement," Appl. Phys. Lett., Vol. 102, No. 15, pp. 151602.1-4.
  17. Kwak, H.J., Yu, D.I., Kim, M.H., Park, H.S., Moriyama, K., Ahn, H.S. and Kim, D.E., 2015, "Interfacial Behavior of Water Droplet on Micro-Nano Structured Surfaces," Trans. Korean Soc. Mech. Eng. B. Vol. 39, No. 5, pp. 449-453. https://doi.org/10.3795/KSME-B.2015.39.5.449
  18. Ahn, H.S., Park, G., Kim, J. and Kim, M.H., 2011, "Wicking and Spreading of Water Droplets on Nanotubes," Langmuir, 28, 5, pp 2614-2619. https://doi.org/10.1021/la204073n
  19. Kang, H.C. and Jacobi, A.M., 2011, "Equilibrium Contact Angles of Liquid Droplets on Ideal Rough Solids," Langmuir, Vol. 27, No. 24, pp. 14910- 14918. https://doi.org/10.1021/la2031413
  20. Yu, D.I., Kwak, H.J., Doh, S.W., Kang, H.C., Ahn, H.S., Kiyofumi, M., Park, H.S. and Kim, M.H., 2015, "Wetting and Evaporation Phenomena of Water Droplets on Textured Surfaces," International Journal of Heat and Mass Transfer, Vol. 90, pp. 191-200. https://doi.org/10.1016/j.ijheatmasstransfer.2015.06.046