Characterization of materials with nanoscopic filler particles by AFM techniques

摘要

In order to modify material properties different kind of filler particles are added to polymer matrices. Miniaturization in electronics, MEMS and photonics applications forces to reduce the size of filler particles, even to submicron and nano scale dimensions. R&D processes as well as later production quality control demand suitable tools and procedures to characterize filler particles, e.g., within polymeric composites. The authors studied different AFM based methods of particle detection and imaging. The underlying purpose was to utilize stress state micrographs of composites with filler particles for deformation measurements. The foreseen digital image correlation technique (DIC) for highest resolution deformation analysis is briefly introduced. In order to understand the impact of filler particles on the mechanical behavior, particle identification and imaging as well as deformation measurement has to be performed on the same micrographs. Main emphasis in this work is made on different imaging modes realizable with scanning probe microscopy (SPM), which can be used to image and to characterize submicron and nano scale fillers. Additionally the influence of surface finishing before the SPM imaging is analyzed, mainly the impact of focused ion beam (FIB) polishing after mechanical polishing. The examined SPM methods for filler characterization are compared to alternative tools like FIB, SEM, AFAM and Laser Scanning Microscopy (LSM).