Mutual solvents, on the other hand, have HSP distances in between those two extremes, indicating a moderate solvent quality towards side chain. Second, we correlate the selectivity towards side chain with high-q structure factor peaks seen in SAXS profile (purple dashed lines in Figure ). This peak corresponding to a spacing of ≈ 2.4 nm can be attributed to lamellar stacking occurring within the solution aggregates . CN solution gives a sharp lamellar stacking peak with a full width at half maximum (FWHM) around 0.02 Å -1 , indicating a highly ordered packing of side chains at RT. It is suggested that such a strong lamellar packing can reduce solvophobic interactions between the aliphatic side chain and solvent, which further results in backbone planarization to give highly anisotropic aggregates . Such an ordered lamellar packing is disrupted by heating, evidenced by the significant broadening of the SAXS lamellar stacking peak at temperature above 115 °C (Figure ). At the same time, the micron sized solution aggregates in CN readily dissolve (Figure ) as the polymer backbone is no longer constrained by strong lamellar ordering and thus can interact freely with CN molecules.