We repeated the experiment but with an increased pH gradient (∆pH/∆t = 2 h -1 , Fig. and h -1 , Fig. ) to validate this observation, and found three noticeable effects; i) the boxes representing the 25-75 percentile of the observed transmittance are narrow (indicating that the final state had stabilized within each step) but broadens when the system is in transition (i.e., the points at which the dashed black line was crossed). ii) The difference between the transitions (indicated with closed and open symbols) widens as the gradient increases. iii) The local minimum to disappear when we increased the gradient to 4 h -1 . Hence, not only does the complexation of PAH and PAA and the dissassembly of the complex PAH-PAA occur at different pH values but both processes are highly dependent on the preceding state of the system (i.e., dependent on the direction of the gradient). Supplementary Information, Fig. validates that this hysteretic behavior can be replicated when the order of the positive and negative gradients is reversed.