Terahertz dynamics of water before and after water shedding from reverse micelles

Picosecond relaxation dynamics of water before and after water shedding from reverse micelles are studied using temperature-dependent terahertz time-domain spectroscopy measurements to clarify the confinement effect of the reverse micelle on the dynamics of water. Before water shedding, the relaxation process due to the collective motion of bulk-like water in the core of the reverse micelle exhibits a considerable slowing down in comparison with that in liquid water as the temperature decreases. This is attributed to the confinement effect of reverse micelles. Moreover, the time constant abruptly drops at the water shedding, and its temperature behavior is similar to that of liquid water afterwards. These results demonstrate that the water extracted from the reverse micelle attains the property of liquid water by reduction in the confinement imposed on the motion of the water.