Looking at both Guinier knees at ~0.025 Å -1 and ~0.1 Å -1 it can be seen that they are preceded by slopes corresponding to elongated, semiflexible objects and are followed by steeper slopes of -3 or lower. Considering the relatively high rigidity of D-A conjugated polymers and their tendency to form fibril aggregates and considering the power law slopes before and after the Guinier knees it is reasonable to assume that these knees correspond to a cross-sectional feature of elongated objects. As a first analysis, we therefore extract the cross-sectional radii by linearization of the cross-sectional Guinier knees based on the equation below.