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Anomalous Freezing of Nano‐Confined Water in Room‐Temperature Ionic Liquid 1‐Butyl‐3‐Methylimidazolium Nitrate
Author(s) -
Abe Hiroshi,
Takekiyo Takahiro,
Yoshimura Yukihiro,
Saihara Koji,
Shimizu Akio
Publication year - 2016
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201501199
Subject(s) - c4mim , ionic liquid , crystallization , differential scanning calorimetry , materials science , nano , analytical chemistry (journal) , chemistry , crystallography , thermodynamics , chromatography , organic chemistry , physics , composite material , catalysis
Non‐crystal formation of ice is investigated by simultaneous X‐ray diffraction and differential scanning calorimetry measurements upon cooling to −100 °C. At room temperature, size‐tunable water confinement (≈20 Å size) in a room‐temperature ionic liquid (RTIL, 1‐butyl‐3‐methylimidazolium nitrate, [C 4 mim][NO 3 ]) exists in a water‐rich region (70–90 mol % D 2 O). The confined water (water pocket) is characterized by almost monodispersive size distribution. In [C 4 mim][NO 3 ]‐ x mol % D 2 O (70< x <94), the absence of sharp Bragg reflections and a distinct exothermal peak indicate that crystallization/cold crystallization both of [C 4 mim][NO 3 ] and D 2 O is suppressed, even upon slow cooling and heating.