Numerical Engineering of Molecular Self-Assemblies in a Binary System of Trimesic and Benzenetribenzoic Acids

Self-assembly of a two-component mixture of trimesic acid (TMA) and 1,3,5-benzene-tribenzoic acid (BTB) was studied by a Monte Carlo calculation. To describe the ordering, the three-state lattice model with homo- and heteromolecular dimeric and trimeric interactions was proposed. We also took advantage of the same symmetry and size effect of TMA and BTB molecules. The molecular interactions between TMA and BTB molecules were calculated by the density functional theory. Our simulations reproduced the self-assembly of all pure and bicomponent phases of TMA and BTB previously found in the experiments. Several new mixed structures were predicted at TMA:BTB ratios of 2:1, 1:1, and 1:2. The conditions of TMA and BTB phase intermixing and coexistence were also clarified by the ground state analysis. The simplest hypothetical structures which might occur due to the mixed trimeric interactions were studied, and their formation conditions were determined.