A comparison of soot nanostructure obtained using two high resolution transmission electron microscopy image analysis algorithms

The present work addresses the validation process of an in-house developed image analysis tool to extract fringe length, tortuosity, and separation from high resolution transmission electron microscopy images of carbonaceous materials. In order to validate the algorithm, we compare fringe properties that are extracted from high resolution transmission electron microscopy (HRTEM) images through (1) the in-house developed tool (new algorithm) and (2) a tool that has been validated and published (previous algorithm). X-ray diffraction and Raman spectroscopy are used to crosscheck the results for fringe length and fringe separation extracted from the HRTEM images. The algorithm of extracting fringe tortuosity is validated by the images of two disordered soot samples, and a heat-pretreated, highly-ordered sample. Tortuosity results are compared with the results of fringe separation. These comparisons validate the algorithm for extracting fringe tortuosity and confirm that tortuosity is an indicator of the degree of disorder within the carbon framework. Statistical results for each property extracted from the HRTEM images by the newly developed image analysis tool are presented in the form of a histogram and characteristic values (mean and median). The characteristic values quantitatively distinguish between the different carbon nanostructures of various soot samples.