Novel Analytical Method of Nanoparticle Dispersibility in Polymer Nanocomposites; TEM-CT and 3D Topological Analysis

Abstract

We established a quantitative analytical method of nanoparticle dispersibility, which includes the following steps; 3D reconstructed image by TEM-CT, particle separation by 3D image analysis, and calculation of a dispersibility index. First the 3D image was reconstructed by a series of 121 projections collected along a single tilt axis on TEM. Second particles were separated from the reconstructed image by binarization. The distance between the gravity centers of particles was measured from the reconstructed images. Finally a dispersibility index was defined as the average of the shortest distances for adjacent nanoparticles divided by an ideal distance. The proposed method was applied for alumina nanoparticles in polymer nanocomposites under different synthetic processes, and the dispersibility of them was calculated by the index. The correlation between the dispersibility as a structure and the transmittance at 700 nm as a function was found to be linear. This method is applicable to evaluate the 3D dispersibility quantitatively for the nanoparticle arrays.