(397p) The Accuracy of Pore Size Distribution Obtained from Non-Local Density Functional Theory in Amorphous Microporous Materials - Polymers and Large Organic Molecules

Typically, amorphous microporous materials have attractive characteristics such as a large surface area and high porosity. Although the industrial utilization of these materials is promising, the accurate survey of their pore size distribution (PSD) is still a challenging task. Pore size distribution (PSD) is an important structural property that facilitates the suitable selection of these materials for specific processes. However, the accurate characterization of their PSD remains a challenging task. The experimental PSD is usually obtained indirectly through N₂ adsorption at 77 K by calculating the PSD using the non-local density functional theory (NLDFT). In this work, we investigated the accuracy of PSD by constructing N₂ isotherms using Gibbs ensemble Monte Carlo simulations. NLDFT-generated PSDs were compared against reference PSDs that were obtained by direct insertion of simulation probes with various sizes. We studied 11 different amorphous materials with surface areas between 5 - 1698 m²/g. We concluded that the NLDFT indeed produced various artifacts in the micropore region resulting in main peaks that did not truly represent the dominant pore size. Most importantly, we propose an alternative method for choosing the smoothing parameter that can produce PSDs that are significantly more consistent with the reference distribution.