2i-2j and Figs. ). Hence, we conclude that the order of appearance of the various 2D phases during annealing is not determined solely by the formation energy value but rather by internal structure optimization during film growth. Another noteworthy finding is that in N-3 and N-5 systems, the volume fractions of the n=1, n=2 and n=3 phases exhibit a complementary distribution, where the n=1 and n=3 phases could result from a decomposition of n=2 phase (Figs. and). In the case of the N-6, the n=2 peak is reduced to a shoulder (Figs. and). It may be caused by the fact that in N-6, the 2D phases are drastically reduced due to an abundant 3Dd phase. In situ GIWAXS shows the opposite volume trend of the 2D and 3Dd phases after 120 seconds of annealing. While the intensity of 2D phases continuously decreases with annealing time, the 3Dd fraction increases. We also observed that the 3Dd slope gradually decreases with the N-value. This might indicate that the continuous decomposition of 2D phases partially serves as the input for the 3Dd phase formation (Fig. ). To understand this process further, it is now important to follow the fate of the cation spacer upon annealing. We have quantified the respective amount of the various monovalent cations present in the layers by 1 H NMR at increasing annealing time. The 1 H NMR technique enabled us to quantitatively analyze the composition of the film at different annealing time points. Details on this technique can be found in our previous works. Supplementary Fig. shows the results for the N-5 system. In good agreement with the in situ GIWAXS, we observed a decrease in the PMA + content and a concomitant relative increase in the FA + content. It is due to the progressive protonation of PMA + and its elimination by volatilization. We have observed the same behavior in the case BA + cation. Moreover, this phenomenon of protonation-volatilization has been described for other monovalent cations employed as additives in the PPS.