Connecting the Nano and the Macro: A Study of Pore Structure in Carbon Black Nanocomposites

Positronium Annihilation Lifetime Spectroscopy (or PALS) uses the lifetime of the bound state of the electron and its antiparticle, the positron (positronium), to determine the pore size, a nanoscale property. By measuring the evolution of pore size as a function of temperature one can determine the phase. Additionally, a macroscopic property called Young’s Modulus affects how much the sample is capable of stretching when a known force is applied. Thus, by measuring the pore size and Young’s Modulus, it is possible to gain a better understanding of how alterations at the microscopic level (pore size) affect the macroscopic properties (Young’s modulus) of carbon filled PDMS polymers. For this study, Young’s modulus and pore size will be systematically measured in samples where the particle size is held constant and fraction of particle (relative to the polymer) is increased and where the volume of the sample occupied by the particles is constant but the particle size is changed.