and its scattering signal becomes weaker. Thus, it is most likely that the aggregate is composed of water droplets extracted from the reverse micelles and that it grows with time. On the other hand, as seen in Fig. 4(b) and (c), during the aggregation process after the water shedding, the THz waveforms due to the sample solution are reproduced for the latter part of the repeated measurement at Tc and for all data below Tc. This indicates that the aggregates of water droplets are dispersed in the solution during the THz measurements and the aggregation process has almost no effect on the response of the water to THz waves.
Almost all the water molecules in the reverse micelle are bulk-like at w0 = 35 because of its large radius (~12 nm) and the large number of water molecules (over 104) [3,6,7,10]. From the following estimation, it is believed that most of the bulk-like water molecules in the reverse micelle are extracted through the water shedding. The radius of the reverse micelle changes from 12 nm to 4 nm upon the water shedding in Fig. 3. The reverse micelle comprises bulk-like water, interfacial water, and the surfactant, where the length of the surfactant is 1.3 nm [5] and the thickness of the interfacial water shell at the surfactant is 0.7 nm [13]. Therefore, the volume of the bulk-like water in the reverse micelle after the water shedding is several percent of that before it. As a result, the THz signal due to bulk-like water after the water shedding is largely due to the water extracted.