The bulk phase behavior of GMO/water/HEA is significantly modified upon HEA polymerization at the different HEA/LAP ratios. At higher LAP concentrations, the temperature range where the Im3m-cubic is formed is extended from 25 to 80°C before a coexisting Pn3m phase appears at 95°C. It is also worth noting that the temperature-induced structural changes become nonreversible after polymerization. Indeed, the growth of polymer chains within a confined geometry is entropically non-favorable, such that the thermal-induced rearrangement or liberation of HEA polymers from aqueous channels is non-reversible and causes the disruption of the cubic phase. Time-resolved synchrotron SAXS measurements on GMO60HEA5 at HEA/LAP of 200/1 permitted the structural effect of HEA polymerization on the Ia3d structure to be followed (see Figure ). The Ia3d-to-Pn3m transition upon water introduced with the LAP solution could be avoided by reducing the total water in the final sample to ~ 35 wt%. During the first 5 min of polymerization, peak broadening of the Ia3d reflections and shifts to higher q values with a significant decrease of the lattice constant, passing from 15.6 to 12.9 nm, are observed. The broadening of the peaks may be from reduced order in the structure upon HEA polymerization inside the nanochannels. The decrease in the lattice GMO headgroups. After 10 min of polymerization, the appearance of three additional peaks at q ~ 0.7 nm -1 , 1.1 nm -1 , and 1.3 nm -1 , corresponds to the formation of the Im3m cubic phase with a lattice constant of ~ 12.2 nm. The intensity of the Im3m reflection peaks increases with time, while the lattice dimension remains primarily unchanged over time.