Centro de Física de Materiales CSIC-UPV/EHU, Materials Physics Center MPC, Paseo Manuel de Lardizabal 5, 20018 San Sebastián, Spain.
Ultramicroscopy. 2011 Jul;111(8):1366-9. doi: 10.1016/j.ultramic.2011.05.001. Epub 2011 May 19.
In this work we present a new AFM based approach to measure the local dielectric response of polymer films at the nanoscale by means of Amplitude Modulation Electrostatic Force Microscopy (AM-EFM). The proposed experimental method is based on the measurement of the tip-sample force via the detection of the second harmonic component of the photosensor signal by means of a lock-in amplifier. This approach allows reaching unprecedented broad frequency range (2-3 × 10(4)Hz) without restrictions on the sample environment. The method was tested on different poly(vinyl acetate) (PVAc) films at several temperatures. Simple analytical models for describing the electric tip-sample interaction semi-quantitatively account for the dependence of the measured local dielectric response on samples with different thicknesses and at several tip-sample distances.
在这项工作中，我们提出了一种新的基于原子力显微镜（AFM）的方法，通过振幅调制静电力显微镜（AM-EFM）在纳米尺度上测量聚合物薄膜的局部介电响应。所提出的实验方法基于通过锁相放大器检测光电传感器信号的二次谐波分量来测量针尖-样品力。这种方法允许在不限制样品环境的情况下达到前所未有的宽频率范围（2-3×10(4)Hz）。该方法在不同温度下的几种聚（醋酸乙烯酯）（PVAc）薄膜上进行了测试。简单的分析模型可以半定量地描述电针尖-样品相互作用，这些模型可以解释不同厚度的样品和几个针尖-样品距离下测量的局部介电响应的依赖性。
