Study on the relationship of chemical structure and order aggregation ability of polyimides: A molecular simulation approach

In our previous research, it reveals that the order aggregation ability of three polyimides (PI-O, PI-M, PI-P) based on BTDA monomer is different with different solvent dosage in experiments. The only difference in chemical structure of these samples is the bridging group in backbone. Molecular mechanics and molecular dynamics were adopted to generate the reasonable molecular models to evaluate the chain regularity and mobility, thus to explain the interesting experimental results and to establish the relationship of the chemical structure and order aggregation ability. For the chain regularity, it is PI-P > PI-M > PI-O from the chain geometry and simulation aggregation. For the chain mobility, it is PI-M > PI-O > PI-P from the rotation barrier energy plots. The simulation result is in accordance with experimental data. It indicates that the effect of the chain regularity and chain mobility on the order aggregation ability can be modulated to some extent by the solvent dosage regulation in experiment. More important, PI-M with special helical geometry and the most mobility of chain showing to display the distinct banded spherulite morphology in solvent limitation is still in researching.