Investigations of the Force−Distance Behavior in Polar Liquids

Scanning force microscopy (force−distance curves) is employed to study the interaction of two SiO x surfaces in a homologous series of hydrogen-bonded liquids. The force−distance behavior and adhesion, determined by solvation effects as well as van der Waals and electrostatic forces, vary systematically with the structure of the liquid molecule. A model is proposed which relates the molecular arrangement in the confining geometry of the tip and the underlying surface to the number of hydroxyl groups of the solvents (hydrogen-bonded networks). For a quantitative evaluation, the spring constant is calculated from the geometric parameters and the eigenfrequencies of the cantilever.