tential between NDI and Th groups and the NDI-Th and Th-Th dihedral potentials. These potentials were parameterised explicitly as they are important for modelling the semiflexibility of the backbone and were not expected to be accurately captured by existing OPLS parameters. They were calculated using a series of constrained quantum-chemical geometry optimisations as described in ref. 48 and ESI Section S1. All parameters used for the AA simulations in this work are tabulated in the ESI, Section S13.