title: Frictional behavior of micro-patterned silicon surface.
abstract: A micro-patterned silicon surface, consisting of depressions with walls having a tilt angle of 30°, was created by photolithography followed by etching. The friction forces in single asperity contact acting between such a surface and an AFM tip was measured in air. This allowed elucidation of the validity of some common friction rules for this particular situation where a small tip traces a surface having roughness features that are significantly larger than the tip itself. The rules that was compared with our data were Amontons' first rule of friction stating that the friction force should be proportional to the load; Amontons' third rule stating that the friction force should be independent of sliding speed, and Euler's rule providing a relation between slope angle and friction coefficient. We found that both nanoscale surface heterogeneities and the μm-sized depressions affect friction forces, and considerable reproducible variations were found along a particular scan line. Nevertheless Amontons' first rule described average friction forces well. Amontons' third rule and Euler's rule were found to be less applicable to our system.
authors.affiliation: KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Chemistry, Division of Surface and Corrosion Science, Drottning Kristinas väg 51, SE-100 44 Stockholm, Sweden. Electronic address: xiaoyanl@kth.se.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Liu
authors.affiliation: Sungkyunkwan University, Department of Chemistry & BK21 School of Chemistry Materials Science, Suwon 440-746, Republic of Korea.
authors.forename: Sang Ho
authors.initials: SH
authors.lastname: Yun
authors.affiliation: KTH Royal Institute of Technology, School of Chemical Science and Engineering, Department of Chemistry, Division of Surface and Corrosion Science, Drottning Kristinas väg 51, SE-100 44 Stockholm, Sweden; SP Technical Research Institute of Sweden, Chemistry, Materials and Surfaces, P.O. Box 5607, SE-114 86 Stockholm, Sweden.
authors.forename: Per M
authors.initials: PM
authors.lastname: Claesson
keywords: Adhesion; Amontons’ rule; Capillary condensation; Coulomb’s rule; Euler’s rule; Friction force; Micro-patterned surface