Breaking of the supercooled state of water by a nanoca vity with disordered atomic configuration I: Freezing behavior of sorbed water into polymethylmethacrylate film as examined by fourier transform infrared spectroscopy

A freezing behavior of sorbed water into an annealed atactic polymethylmethacrylate (PMMA) film was examined by Fourier transform infrared (IR) spectroscopy. Temperature dependence of IR spectra of the sorbed water indicated that nonfreezable water in the PMMA film formed associated waters on cooling and were not universally nonfreezable. Its freezing temperature was found to be 249 K, which is much higher than the homogeneous nucleation temperature of water, 236 K. This result suggests that a disordered atomic configuration of a nanocavity wall with hydrogen bond acceptors induces a breaking of the supercooled state of water. The former two findings were visibly clarified by the vibrational spectroscopic method for the first time, and the latest finding was different from the literature on supercooled water in small spaces.