Direct measurement of kinetic properties of molecular layer by electric field tweezers system

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The electric field tweezers is the measurement system of the local surface properties of the soft materials. The system excites the surface mechanical vibration on the surface with non-contact manner with dielectric force. Electric field is applied by a needle electrode set just above the sample surface, which picks up the surface of the dielectric materials. The amplitude of the surface deformation gives the measure for the surface tension as restoring force, while the time constant of the deformation yields the viscosity. We can determine the shear viscosity and the surface tension uniquely by measuring the dynamic behavior of the liquid film with non-contact manner.In this study, we applied the electric tweezers system to measure the local mechanical properties of liquid thin films. We can determine the DLVO interaction of the sample from the time constants of symmetric (spray) and asymmetric (bending) modes. The system was also employed for the rapid measurement of highly viscous liquids. The principle experimentally proved is now considered for the application of very slow and accurate mechanical actuator.