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

电场镊子是软材料局部表面性质的测量系统。该系统利用介电力以非接触的方式激励表面的机械振动。通过设置在样品表面正上方的针状电极施加电场，该电极拾取介质材料的表面。表面变形的幅度给出了表面张力作为恢复力的量度，而变形的时间常数产生了粘度。通过非接触式测量液膜的动态行为，可以唯一地确定液膜的剪切粘度和表面张力。在本研究中，我们应用电动镊子系统来测量液膜的局部力学性能。我们可以根据对称(喷射)和非对称(弯曲)模的时间常数来确定样品的DLVO相互作用。该系统还用于高粘度液体的快速测量。实验证明的原理现在被认为是非常慢和精确的机械执行器的应用。

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.