title: Modulation of friction dynamics in water by changing the combination of the loop- and graft-type poly(ethylene glycol) surfaces.
abstract: A Velcro-like poly(ethylene glycol) (PEG) interface was prepared in order to control the friction dynamics of material surfaces. Graft- and loop-type PEGs were formed on mirror-polished Ti surfaces using an electrodeposition method with mono- and di-amine functionalized PEGs. The friction dynamics of various combinations of PEG surfaces (i.e., graft-on-graft, loop-on-loop, graft-on-loop, and loop-on-graft) were investigated by friction testing. Here, only the Velcro-like combinations (graft-on-loop and loop-on-graft) exhibited a reversible friction behavior (i.e., resetting the kinetic friction coefficient and the reappearance of the maximum static friction coefficient) during the friction tests. The same tendency was observed when the molecular weights of loop- and graft-type PEGs were tested at 1 k and 10 k, respectively. This indicates that a Velcro-like friction behavior could be induced by simply changing the conformation of PEGs, which suggests a novel concept of altering polymer surfaces for the effective control of friction dynamics.
authors.affiliation: Department of Organic Biomaterials, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Tokyo 101-0062, Japan. yui.org@tmd.ac.jp.
authors.forename: Ji-Hun
authors.initials: JH
authors.lastname: Seo
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Tsutsumi
authors.forename: Akinori
authors.initials: A
authors.lastname: Kobari
authors.forename: Masayuki
authors.initials: M
authors.lastname: Shimojo
authors.forename: Takao
authors.initials: T
authors.lastname: Hanawa
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Yui