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Publication Citation: Effects of Surface Free Energy and Relative Humidity on Friction and Image Contrast Measured with Lateral Force Microscopy

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Author(s): Tinh Nguyen; Lijiang Chen; Xiaohong Gu;
Title: Effects of Surface Free Energy and Relative Humidity on Friction and Image Contrast Measured with Lateral Force Microscopy
Published: March 03, 2010
Abstract: Effects of sample surface free energy (s) and relative humidity (RH) of the tip-sample environment on image contrast and friction characteristics measured with lateral force microscopy (LFM) have been investigated. Samples having a wide range of surface free energies were fabricated by combining microcontact printing, silane vapor deposition, and UV/O3 treatment. Humidity in the tip-sample environment was controlled using a chamber enclosing the AFM head. The friction difference between two chemically-different domains increases slightly at low RH, reaches a maximum at elevated RH, and then decreases. This friction behavior is proportional to the s difference of the two domains. The LFM image contrast between domains follows closely with their s difference. By optimizing RH, LFM is found to be capable of discerning two domains having a difference in their surface free energy as small as 6.4 mJ/m2. The enhanced image contrast at elevated RHs is attributed to the capillary force, which is a function of surface free energy of the sample.
Proceedings: Adhesion Society Meeting
Pages: 3 pp.
Location: Daytona Beach , FL
Dates: February 21-24, 2010
Keywords: AFM; friction; chemical; humidity; imaging; surface free energy
Research Areas: Materials Science, Building and Fire Research, Nanotechnology, Measurements