The surface pressure of the adsorption membrane: the surfactant adsorbs at the gas-liquid interface to form an adsorption membrane. For example, a frictionless movable float is placed on the interface, and the float pushes the adsorbed plasma membrane along the solution surface. The membrane generates a pressure on the float. This pressure is called the surface pressure.
Surface viscosity: Like surface pressure, surface viscosity is a property exhibited by insoluble molecular membranes. Suspend a platinum ring with a thin metal wire so that its plane touches the water surface of the sink. Rotate the platinum ring. The platinum ring is hindered by the viscosity of the water, and the amplitude gradually decreases. Based on this, the surface viscosity can be measured by firstly on the surface of pure water An experiment was conducted to measure the amplitude attenuation, and then the attenuation after the formation of the surface film was measured, and the viscosity of the surface film was determined from the difference between the two.
The surface viscosity is closely related to the firmness of the surface film. Since the adsorption film has surface pressure and viscosity, it must be elastic. The greater the surface pressure of the adsorption membrane and the higher the viscosity, the greater the elastic modulus. The elastic modulus of the surface adsorption film is of great significance in the foam stabilization process.