SOOT MORPHOLOGY - AN APPLICATION OF IMAGE-ANALYSIS IN HIGH-RESOLUTIONTRANSMISSION ELECTRON-MICROSCOPY

Interest in the fine structure of soots and carbon blacks is motivated by a variety of possible applications. The structure provides informa tion on the origins of the particles and on their adsorptive and react ive properties. This paper describes a method for quantification of th e structure of soots and carbon blacks based on direct electron micros copic observation followed by image analysis of these materials. High- resolution transmission electron microscopy (HRTEM) provides a very de tailed observation of particle structure. The differences in soot stru cture, because of its complexity, may not be easily quantifiable with the human eye; therefore, high-level computer software has been used t o manipulate HRTEM images. This technique involves the application of fast Fourier transforms (FFT) to single particles and the measurement; of characteristic parameters such as interplanar spacings and crystal lite sizes from these particles. The methodology and application of th is characterization technique are presented here. Results are shown fo r different samples obtained from soot and carbon black particles sele cted to illustrate the capabilities of the methodology. Quantitative i nformation can be obtained on structural characteristics, e.g., interp lanar spacing, circularity, orientation, elongation, and length distri bution of lattice fringes, as well as on the fractional coverage of th e extracted pattern. (C) 1996 Wiley-Liss, Inc.