Fig. 5: STM characterisation of polymer 4 and 5.

a Sequence of polymer 4 with predominant AB coupling (15 nm × 15 nm, V = 573 mV, I = 78 pA). b Formation of kinks in the backbone (10 nm × 10 nm, V = 176 mV, I = 90 pA). Pink and orange ovals correspond to c2 and c3 coupling defects, respectively, as illustrated in Supplementary Figs. S12 and S13. c High-resolution STM images of polymer 5 (13 nm × 13 nm, V = 247 mV, I = 140 pA). d Formation of kinks in the backbone (10 nm × 10 nm, V = 247 mV, I = 140 pA). The pink oval corresponds to a c2 defect (see Supplementary Fig. S17). Geometry-optimised molecular models are superposed onto images in (a) and (c), while those of only the backbone are superposed onto images in (b) and (d) to help visualise the kinks.