Next, we take the optimized single-chain structures to set up supercells of N = 100 PTBT chains for both regioregularities. Since there is no experimental data on the structural properties of this novel polymer present in the literature, we will simulate the self-assembly of conjugated PTBT chains from scratch. This means we let the system self-associate by temperature-annealing from a very high temperature, isotropic phase to room-temperature conditions. Such an approach has been used successfully for similar systems. The initial systems are cooled down from 1500 K to 300 K in the NPT ensemble over a time period of 10 ns (cf. Fig. ). After the systems are equilibrated at room-temperature, all polymer chains have been aggregated into one big cluster, respectively (cf. Fig. ). In the HT-HT system, we observe neighboring chains forming an ordered region in the center of the cluster, where the backbones are planar and stacked together in a face-to-face manner along the crystal (growth) a-axis. The blue-colored area depicts three stacks of chains arranged in a lamellar fashion along the c-axis. Going to the outer regions of such cluster, its ordering decreases due to surface effects which lead to backbone bending and distortion of the crystalline alignment. Here, we observe a mix of different substructures (small stacks similar to the center, pairs of bent chains, and even bigger arrangments of those chain pairs; cf. Fig. ).