The data for 2NapFF-TBA show a similar peak, which shows a gradient of 0.53, again consistent with a polyelectrolyte-like system. However, unlike 2NapFF-Na, the peak is evident at lower concentrations (15 mg/mL) indicating that there is interaction between the flexible cylinders in solution at a lower concentration than for 2NapFF-Na. Plotting the change in correlation length (Figure ) shows that 2NapFF-TBA has a more pronounced drop in correlation length with increasing concentration and that at 75 mg/mL the correlation length reached is far smaller than that seen for the same concentration of 2NapFF-Na (10 nm versus 22 nm respectively). Thus, the counterion not only controls the micellar structure but also influences the aggregate interactions via modification of the micellar dimensions. The extended polyelectrolyte-like conformation of these interacting chains in the semi-dilute regime has implications for their alignment. As the concentration of 2NapFF-Na increases, the samples display an alignment parallel to the long axis of the capillary in which they are measured in the 2D SAXS data (Figure ). The degree of alignment can be quantified by fitting the <P2> order parameter (Figure and Figure ) and the samples show the distinctive Schlieren texture of a nematic liquid crystal (Figure , Figure ). There is an isotropic to nematic transition at a 2NapFF-Na concentration of approximately 20 mg/mL, corresponding to the concentration at which the correlation length peak becomes visible in the 1D pattern.