中国物理B ›› 2009, Vol. 18 ›› Issue (1): 231-237.doi: 10.1088/1674-1056/18/1/038

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Effect of micro-dimple patterns on capillary pull-off force and friction force of silicon surface

刘永合1, J.A.Schaefer1, 董云开2, 张向军3   

  1. (1)Institute of Physics and Center of Micro/nano Technology, Technich University of Ilmenau, PF 100565, Germany; (2)State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, China; (3)State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, China;Institute of Physics and Center of Micro/nano Technology, Technich University of Ilmenau, PF 100565, Germany
  • 收稿日期:2008-05-19 修回日期:2008-08-13 出版日期:2009-01-20 发布日期:2009-01-20
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos 50575123 and 50730007), and China Scholarship Council (CSC) and German Research Foundation (DFG).

Effect of micro-dimple patterns on capillary pull-off force and friction force of silicon surface

Zhang Xiang-Jun(张向军)a)b)†, Dong Yun-Kai (董云开)a), Liu Yong-He(刘永合)b), and J. A. Schaeferb)   

  1. a State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, China; b Institute of Physics and Center of Micro/nano Technology, Technich University of Ilmenau, PF 100565, Germany
  • Received:2008-05-19 Revised:2008-08-13 Online:2009-01-20 Published:2009-01-20
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos 50575123 and 50730007), and China Scholarship Council (CSC) and German Research Foundation (DFG).

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摘要： A microtribometer is used to measure and compare pull-off forces and friction forces exerted on (a) micro-dimpled silicon surfaces, (b) bare silicon surfaces, and (c) octadecyltrichlorosilane (OTS) treated silicon surfaces at different relative humidity (RH) levels separately. It is found that above a critical RH level, the capillary pull-off force increases abruptly and that the micro-dimple textured surface has a lower critical RH value as well as a higher pull-off force value than the other two surfaces. A micro topography parameter, namely sidewall area ratio, is found to play a major role in controlling the capillary pull-off force. Furthermore, micro-dimpled silicon surface is also proved to be not sensitive to variation in RH level, and can realize a stable and decreased friction coefficient compared with un-textured silicon surfaces. The reservoir-like function of micro dimples is considered to weaken or avoid the breakage effect of liquid bridges at different RH levels, thereby maintaining a stable frictional behaviour.

关键词: micro-dimpled surface, capillary pull-off force, frictional property, relative humidity

Abstract: A microtribometer is used to measure and compare pull-off forces and friction forces exerted on (a) micro-dimpled silicon surfaces, (b) bare silicon surfaces, and (c) octadecyltrichlorosilane (OTS) treated silicon surfaces at different relative humidity (RH) levels separately. It is found that above a critical RH level, the capillary pull-off force increases abruptly and that the micro-dimple textured surface has a lower critical RH value as well as a higher pull-off force value than the other two surfaces. A micro topography parameter, namely sidewall area ratio, is found to play a major role in controlling the capillary pull-off force. Furthermore, micro-dimpled silicon surface is also proved to be not sensitive to variation in RH level, and can realize a stable and decreased friction coefficient compared with un-textured silicon surfaces. The reservoir-like function of micro dimples is considered to weaken or avoid the breakage effect of liquid bridges at different RH levels, thereby maintaining a stable frictional behaviour.

Key words: micro-dimpled surface, capillary pull-off force, frictional property, relative humidity

中图分类号:  (Dynamics (capillary waves))

  • 68.03.Kn
68.08.-p (Liquid-solid interfaces) 68.15.+e (Liquid thin films)