Mapping of the komplex elastic modulus of microstructured polymer samples

为了更好地理解纳米科学中的基本现象以及纳米材料和纳米技术的发展，需要在纳米尺度上研究聚合物的机械性能。这也适用于在纳米技术的几个领域中使用的聚合物。为此，只能使用亚微米尺度的空间分辨率仪器，例如原子力显微镜（AFM）和纳米压头。两种仪器定量测定机械性能的重要缺陷，即奥利弗和法尔的纳米压头理论的大部分应用以及原子力显微镜尖端几何形状知识的缺乏，将在本项目开始时通过测量结果的比较来解决。该项目的核心是开发和验证力调制技术作为一种测量技术，具有亚微米空间分辨率，用于确定和绘制损耗模量。用AFM和纳米压头获得的结果将与其他已建立的技术进行比较，例如动态力学分析（DMA）。由于其在纳米尺度上的独特分辨率，原子力显微镜被用于研究和绘制非均质聚合物样品的局部性质。研究和确定力调制技术所能达到的空间分辨率，并确定聚合物薄膜、微结构聚合物共混物和共聚物的损耗模量，是该项目的最后阶段的目标。

A better understanding of basic phenomena in the nanoscience and the development of nanomaterials and nanotechnologies implies the investigation of the mechanical properties of polymers at the nanoscale. This is valid also for polymers which are employed in several fields of the nanotechnology. To this aim only instruments with a spatial resolution in the submicrometer scale can be used, e.g. the Atomic Force Microscope (AFM) and the nanoindenter.Important drawbacks for the quantitative determination of the mechanical properties with both instruments, i.e. most of all the application of the theory of Oliver and Pharr for the nanoindenter and the lack of knowledge of the geometry of the tip for the AFM, will be resolved at the beginning of this project through the comparison of the measurements.The core of the project is the development and validation of the force-modulation-technique as a measuring technique with submicrometer spatial resolution for the determination and the mapping of the loss modulus. The results obtained with the AFM and with the nanoindenter will be compared with other established techniques, e.g. the Dynamic Mechanical Analysis (DMA).Owing to its unique resolution at the nanoscale, the AFM is predestinated for the investigation and the mapping of the local properties of inhomogeneous polymer samples. The investigation and determination of the spatial resolution attainable with the force-modulation-technique and the determination of the loss modulus of thin polymer films, microstructurerd polymer blends and copolymers is the aim of the end stage of the project.