Soprunyuk, ViktorViktorSoprunyukSchranz, WilfriedWilfriedSchranzHuber, PatrickPatrickHuber2020-04-072020-04-072016-08EPL 4 (115): 46001 (2016-08)http://hdl.handle.net/11420/5675Copyright © 2016 EPLA. Dynamical mechanical analysis (DMA)(f = 0.2.100Hz) is used to study the dynamics of confined water in mesoporous Gelsil (2.6nm and 5nm pores) and Vycor (10 nm) in the temperature range from T = 80K to 300 K. Confining water into nanopores partly suppresses crystallization and allows us to perform measurements of supercooled water below 235K, i.e., in water's so-called no man's land', in parts of the pores. Two distinct relaxation peaks are observed in tan δ around T1 ≈ 145K (P1) and T2 ≈ 205K (P2) for Gelsil 2.6 nm and Gelsil 5 nm at 0.2Hz. Both peaks shift to higher T with increasing pore size d and change with f in a systematic way, typical of an Arrhenius behaviour of the corresponding relaxation times. For P1 we obtain an average activation energy of Ea = 0.47 eV, in good agreement with literature values, suggesting that P1 corresponds to the glass transition of supercooled water. The observation of a pronounced softening of the Young's modulus around 165K (for Gelsil 2.6 nm at 0.2 Hz) supports the conjecture of a glass-to-liquid transition in the vicinity of P1. In addition we find a clear-cut (1/d)-dependence of the calculated glass transition temperatures which extrapolates to Tg(1/d = 0) = 136 K, in agreement with the traditional value of water.en0295-507520164Journal Article10.1209/0295-5075/115/46001Other