Aggregation Analysis of Simulated Electric Field Poled Poly(methyl methacrylate) Doped with Tricyanopyrroline Chromophores.

Dipolar chromophore molecules embedded with noncentrosymmetric alignment in a polymer matrix may exhibit nonlinear electro-optical (EO) activity. The polymer matrix serves as a host, stabilizing the alignment of chromophores and conserving the EO activity in the glass state. However, at high chromophore number densities and/or elevated temperatures, aggregation may occur, resulting in a loss or at least altered EO response. Here, we present a novel and general Python-based tool for the analysis of aggregation and phase behavior. Our method provides frequency distributions of aggregate size (i.e., number of involved molecules) and aggregate types (i.e., the mutual molecular arrangement). The aggregation analysis is illustrated for the molecular dynamics simulation of electric field poling and relaxation (i.e., the analysis of the phase behavior). The analysis method helps to identify and visualize the process of aggregation and can be adapted to various models (e.g., liquid crystalline materials) if the shape of the molecule of interest is properly considered.