Modeling the Self-Assembly of Benzenedicarboxylic Acids Using Monte Carlo and Molecular Dynamics Simulations

We present a theoretical modeling Study of self-assembly Of Molecules into two-dimensional (2D) hydrogen-bonded networks. We compare two computational techniques, molecular dynamics (MD) and Monte Carlo (MC) Calculations, in order to find out whether these computational techniques are efficient in modeling the process of self-assembly and in predicting the ordered supramolecular structures. Terephthalic acid, isophthalic acid, and phthalic acid, which have been widely studied experimentally, are used as test systems. According to both computational techniques, terephthalic acid molecules form ordered Structures made of parallel molecular chains (same as observed in experiment) at high Surface coverage, whereas less symmetric isophthalic and phthalic acid molecules mostly form disordered arrangements of zigzag chains or long isolated zigzag chains. Both computational techniques reproduce the supramolecular Structure of terephthalic acid, the most symmetric of these molecules. However, MD simulations are more robust, whereas MC simulation results are very dependent oil the choice of the starting Structure.