title: Tuning the Friction Characteristics of Gecko-Inspired Polydimethylsiloxane Micropillar Arrays by Embedding Fe₃O₄ and SiO₂ Particles.
abstract: In order to improve stiffness of polydimethylsiloxane (PDMS) pillars while maintaining high friction, the effects of embedding Fe3O4 and SiO2 particles on the friction behavior of PDMS micropillars are studied. Both types of added particles increase the stiffness of the PDMS composite, but affect the friction behavior differently. The frictional force of the fibrillar array fabricated with Fe3O4/PDMS composite decreases initially, then increases as the particle content increases. For silica/PDMS composite pillars, the frictional force is independent of the particle density. Characterization by scanning electron microscopy shows that Fe3O4 particles are distributed uniformly in the PDMS matrix at low concentration, but heterogeneous distribution is observed at high particle loading, with particles being hindered from penetrating into the pillars. For silica/PDMS composite pillars, the particles distribute homogeneously inside the pillars, which is attributed to the formation of hydrogen bonding between silica particles and PDMS. The difference in particle distribution behavior is used to explain the observed difference in the friction response of these two composite systems.
authors.affiliation: †School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China.|‡Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720, United States.
authors.forename: Ye
authors.initials: Y
authors.lastname: Tian
authors.affiliation: ‡Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720, United States.
authors.forename: Zizhou
authors.initials: Z
authors.lastname: Zhao
authors.affiliation: ‡Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720, United States.
authors.forename: Gina
authors.initials: G
authors.lastname: Zaghi
authors.affiliation: ‡Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720, United States.
authors.forename: Yongkwan
authors.initials: Y
authors.lastname: Kim
authors.affiliation: †School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China.
authors.forename: Dongxing
authors.initials: D
authors.lastname: Zhang
authors.affiliation: ‡Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720, United States.
authors.forename: Roya
authors.initials: R
authors.lastname: Maboudian
keywords: PDMS; Young’s modulus; friction; gecko-inspired adhesives; micropillar