Experimental investigation of adhesion characteristics of cleavage mica surfaces with a liquid layer

The surface mechanics of adhesion between cleavage mica surfaces were studied experimentally by measuring the normal forces between the atomically smooth surfaces. The surface force apparatus with a resolution of 0.02 mN was used to continuously record the dynamic strain signals for real-time, dynamic measurements. The system measured the pull-off forces between the two cleavage mica surfaces with a liquid layer in an approach-separation experiment. The tests show that a thin layer of liquid between the two cleavage mica surfaces increases the pull-off force with the force increasing with the larger liquid thickness. When the middle liquid layer is a high kinematic viscosity liquid, such as neutral paraffine, the viscous force greatly affects the adhesion characteristics. When the liquid layer is a low kinematic viscosity liquid, such as deionized water, the surface energy of the liquid layer strongly affects the adhesion characteristics.