Abstract
Nanoconfined liquid water can transform into low-dimensional ices whose crystalline structures are dissimilar to any bulk ices and whose melting point may significantly rise with reducing the pore size, as revealed by computer simulation and confirmed by experiment. One of the intriguing, and as yet unresolved, questions concerns the observation that the liquid water may transform into a low-dimensional ice either via a first-order phase change or without any discontinuity in thermodynamic and dynamic properties, which suggests the existence of solid-liquid critical points in this class of nanoconfined systems. Here we explore the phase behavior of a model of water in carbon nanotubes in the temperature-pressure- diameter space by molecular dynamics simulation and provide unambiguous evidence to support solid-liquid critical phenomena of nanoconfined water. Solid-liquid first-order phase boundaries are determined by tracing spontaneous phase separation at various temperatures. All of the boundaries eventually cease to exist at the critical points and there appear loci of response function maxima, or the Widom lines, extending to the supercritical region. The finite-size scaling analysis of the density distribution supports the presence of both first-order and continuous phase changes between solid and liquid. At around the Widom line, there are microscopic domains of two phases, and continuous solid-liquid phase changes occur in such a way that the domains of one phase grow and those of the other evanesce as the thermodynamic state departs from the Widom line.
| Original language | English |
|---|---|
| Pages (from-to) | 8221-8226 |
| Number of pages | 6 |
| Journal | Proceedings of the National Academy of Sciences of the United States of America |
| Volume | 112 |
| Issue number | 27 |
| DOIs | |
| Publication status | Published - Jul 7 2015 |
Fingerprint
Keywords
- Carbon nanotube
- Ice
- Solid-liquid critical point
- Water
- Widom line
ASJC Scopus subject areas
- General
Cite this
Solid-liquid critical behavior of water in nanopores. / Mochizuki, Kenji; Koga, Kenichiro; Sastry, Srikanth.
In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 112, No. 27, 07.07.2015, p. 8221-8226.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Solid-liquid critical behavior of water in nanopores
AU - Mochizuki, Kenji
AU - Koga, Kenichiro
AU - Sastry, Srikanth
PY - 2015/7/7
Y1 - 2015/7/7
N2 - Nanoconfined liquid water can transform into low-dimensional ices whose crystalline structures are dissimilar to any bulk ices and whose melting point may significantly rise with reducing the pore size, as revealed by computer simulation and confirmed by experiment. One of the intriguing, and as yet unresolved, questions concerns the observation that the liquid water may transform into a low-dimensional ice either via a first-order phase change or without any discontinuity in thermodynamic and dynamic properties, which suggests the existence of solid-liquid critical points in this class of nanoconfined systems. Here we explore the phase behavior of a model of water in carbon nanotubes in the temperature-pressure- diameter space by molecular dynamics simulation and provide unambiguous evidence to support solid-liquid critical phenomena of nanoconfined water. Solid-liquid first-order phase boundaries are determined by tracing spontaneous phase separation at various temperatures. All of the boundaries eventually cease to exist at the critical points and there appear loci of response function maxima, or the Widom lines, extending to the supercritical region. The finite-size scaling analysis of the density distribution supports the presence of both first-order and continuous phase changes between solid and liquid. At around the Widom line, there are microscopic domains of two phases, and continuous solid-liquid phase changes occur in such a way that the domains of one phase grow and those of the other evanesce as the thermodynamic state departs from the Widom line.
AB - Nanoconfined liquid water can transform into low-dimensional ices whose crystalline structures are dissimilar to any bulk ices and whose melting point may significantly rise with reducing the pore size, as revealed by computer simulation and confirmed by experiment. One of the intriguing, and as yet unresolved, questions concerns the observation that the liquid water may transform into a low-dimensional ice either via a first-order phase change or without any discontinuity in thermodynamic and dynamic properties, which suggests the existence of solid-liquid critical points in this class of nanoconfined systems. Here we explore the phase behavior of a model of water in carbon nanotubes in the temperature-pressure- diameter space by molecular dynamics simulation and provide unambiguous evidence to support solid-liquid critical phenomena of nanoconfined water. Solid-liquid first-order phase boundaries are determined by tracing spontaneous phase separation at various temperatures. All of the boundaries eventually cease to exist at the critical points and there appear loci of response function maxima, or the Widom lines, extending to the supercritical region. The finite-size scaling analysis of the density distribution supports the presence of both first-order and continuous phase changes between solid and liquid. At around the Widom line, there are microscopic domains of two phases, and continuous solid-liquid phase changes occur in such a way that the domains of one phase grow and those of the other evanesce as the thermodynamic state departs from the Widom line.
KW - Carbon nanotube
KW - Ice
KW - Solid-liquid critical point
KW - Water
KW - Widom line
UR - http://www.scopus.com/inward/record.url?scp=84936870732&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84936870732&partnerID=8YFLogxK
U2 - 10.1073/pnas.1422829112
DO - 10.1073/pnas.1422829112
M3 - Article
AN - SCOPUS:84936870732
VL - 112
SP - 8221
EP - 8226
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
SN - 0027-8424
IS - 27
ER -