Plasmonic Observation of High-Density Nanoclustering in Low-Temperature HO.

There has been considerable scientific interest in comprehending the behavior and phase transitions of HO at the nanoscale in low temperatures. Herein, a highly sensitive and nondestructive surface plasmonic detection system operated at low temperatures to investigate the real-time nanoscale variation in HO density from a rapidly cooled thin ice layer formed at 77 K is employed. The nanoslit device exhibits a distinct plasmonic response at 180-250 K, correlated to an increase in the local density of HO at the nanometer scale. Along with theoretical analyses, it is revealed that high-density HO clusters form by vigorous aggregation of HO molecules within the interphase liquid region between polymorphic ice crystals. The utilization of ice-active materials, known to inhibit ice growth, suppresses the initiation of such high-density nanoclustering at 180 K. These results contribute to the comprehension of the interplay between polymorphic crystals and density-variant interphases in low-temperature HO systems.