After calculating the force field parameters for the minimal model (representing the backbone of the polymer), the sidechains are attached to the designated positions, i.e., all methyl groups in the minimal polymer model, the sidechain force field parameters (united-atom and directly taken from OPLS-FF) are added, and the atomic charges around the sidechain-backbone connection points are corrected to maintain the whole repeat-unit charge neutrality (step 4 in scheme 1), see SI, sections S1.3 and S1.4. Last, polymer chain models (i.e., coordinates and force field files) with desired degrees of polymerisation (e.g., in this study n = 10 since the effect of Mw on the calculated electronic structure properties was found to be negligible from n ≥ 10) are generated (step 5 in scheme 1). Note that the Lennard-Jones parameters for all backbone atoms were also taken from OPLS force field to be consistent with the sidechain parameters.