Changing the counterion used translates directly into differences in solution properties. The 2NapFF-TBA solutions are significantly more viscous than the 2NapFF-Na solutions (Figure ). This increase in viscosity could be partly the reason for the inability to align 2NapFF-TBA in a magnetic field. This however cannot be the only factor as the viscosity of 2NapFF-TBA at 5 mg/mL is similar to that of 2NapFF-Na at concentrations of 30-50 mg/mL (Figure ), which can be aligned. The extensional viscosities are very different; the extensional relaxation time (λE) was studied at 25 mg/mL using the dripping-onto-substrate technique. For 2NapFF-TBA, λE is too large to measure (the filament dries out before breaking) whereas for 2NapFF-Na λE = 14.6 ± 6.5 ms (Figure ). WAXS data show that the degree of order in each system depends on the counterion used (Figure S14 and S15). For 2NapFF-Na, peaks in the WAXS appear above 10 mg/mL, coinciding with the onset of alignment. The peaks in the WAXS arise from each cylinder lining up in the same direction as the cylinder next to it and this "confinement" leading to ordering in the packing. For 2NapFF-TBA, the WAXS only shows a single peak in this region (Figure ) corresponding to the radius of the much thinner 2NapFF-TBA cylinder. Air-dried aligned fibers were prepared, and fiber X-ray diffraction (fXRD) data collected (these are not dehydrated and retain some water). These data (Figure ) show that on drying to form the stalk, the 2NapFF-Na shows a classic fiber diffraction pattern consistent with flexible fibers aligned along the sample axis. The 2NapFF-TBA diffraction pattern is more consistent with randomly oriented crystallites which give rise to much sharper reflections. In both cases, organization along the fiber axis appears similar while the packing and lateral organization are different. We can therefore control the degree of order within the system both in the solution and dry state by choice of counterion. There are analogies here with controlling the degree of order in DNA stalks with humidity. Subjecting the micellar solutions at low concentrations to a heat-cool cycle can have a profound effect on their structure. 8 Heat-cool cycles were performed on solutions of 2NapFF-Na at a concentration of 10, 40, and 75 mg/mL. In all cases, the radii of the cylinders decrease, and the Kuhn length is reduced (Figure ). This is extremely marked in the highest concentration samples which now fits to a flexible cylinder form factor, showing that the rigidity has been lost (Table ). The samples post heating also show a reduced intensity correlation peak, and this peak has shifted to higher Q, thus a lower value of ξ, reflecting their reduced radii. The orientation in the 2D scattering pattern is lost and the samples are now isotropic (Figure ). The lack of order can also be seen in the polarized microscopy (Figure 3b and 3c; Figure S32 and S33) and NMR experiments (Figure and S27) where a change in the texture and a loss of the splitting of the D2O peak are seen respectively. Before heat-cool, 2NapFF-Na samples exhibit a loss modulus (Gʺ) less than the storage modulus (Gʹ) with the exception of 2NapFF-Na at 100 mg/mL (Figure , Figure ). At concentrations of 25 mg/mL and greater, G¢ is higher than G² in small amplitude oscillatory shear after a heat-cool cycle, although tand > 0.16.