Interfacial modulus and surfactant coated surfaces

The Interfacial Modulus (GS) describes the ease at which a functional group within a solid's outer layer can move from a buried position to a more protruding orientation or vice versa. GS is typically sensitive to the out-most layer of the solid's molecules. It can be measured using a Centrifugal Adhesion Balance (CAB) configuration that is aligned for drop sliding at zero normal force. Currently, however, there is no way of measuring GS independently of CAB experiments. In a desire to find independent means for evaluating the interfacial modulus, we present here an alternative way to estimate GS through Surface Force Apparatus estimates of the force associated with single functional groups within such a layer.