title: AFM interaction study of alpha-alumina particle and c-sapphire surfaces at high-ionic-strength electrolyte solutions.
abstract: Ionic strength dependence of interaction and friction forces between hydrophilic alpha-alumina particles and c-sapphire surfaces (0001) were investigated under basic pH conditions using the colloidal probe method. The compression of the double layer could be seen from force-distance curves as the ionic strength of the solution increased. The forces were repulsive at all ionic strengths measured, even though the interaction distance changed drastically. No jump to contact occurred. The interaction distance decreased from about 20 nm in 10(-3) M KCl solution to about 7 nm in the 1 M KCl case. The lubricating effect of hydrated cations on the lateral friction force was demonstrated at high electrolyte concentrations. This was attributed to more hydrated cations being present in the solution. The friction behavior was closely related to the short-range repulsive forces between the alpha-alumina surfaces at pH 11.
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), Anagahora 2266-98, Shimoshidami, Moriyama-ku, Nagoya-shi, Aichi 463-8560, Japan. huseyin-yilmaz@aist.go.jp
authors.forename: Huseyin
authors.initials: H
authors.lastname: Yilmaz
authors.forename: Kimiyasu
authors.initials: K
authors.lastname: Sato
authors.forename: Koji
authors.initials: K
authors.lastname: Watari