A method for reliable measurement of relative frictional properties of different self-assembled monolayers using frictional force microscopy

A practical method of preparing silica surfaces coated with spatially segregated silane amphiphiles for the purpose of accurately comparing their frictional properties is discussed. The method uses a UV/ozone photochemical process that utilizes spatially selective decomposition and deposition of amphiphiles. By using a scanning electron microscope (SEM) grid, selected areas of a self-assembled monolayer (SAM) are either exposed to or protected from the degradation process. The process shows no detrimental effect to the silica surface, nor does it affect the properties of the masked monolayer remaining after degradation. Contact angle goniometry and friction force measurements of several organosilane SAMs demonstrate the effectiveness of the method. (C) 2001 Elsevier Science B.V. All rights reserved.