Abnormal Properties of Low‐Dimensional Confined Water

Abstract

Water molecules confined to low‐dimensional spaces exhibit unusual properties compared to bulk water. For example, the alternating hydrophilic and hydrophobic nanodomains on flat silicon wafer can induce the abnormal spreading of water (contact angles near 0°) which is caused by the 2D capillary effect. Hence, exploring the physicochemical properties of confined water from the nanoscale is of great value for understanding the challenges in material science and promoting the applications of nanomaterials in the fields of mass transport, nanofluidic designing, and fuel cell. The knowledge framework of confined water can also help to better understand the complex functions of the hydration layer of biomolecules, and even trace the origin of life. In this review, the physical properties, abnormal behaviors, and functions of the confined water are mainly summarized through several common low‐dimensional water formats in the fields of solid/air–water interface, nanochannel confinement, and biological hydration layer. These researches indicate that the unusual behaviors of the confined water depend strongly on the confinement size and the interaction between the molecules and confining surface. These diverse properties of confined water open a new door to materials science and may play an important role in the future development of biology.

The coming of age of water channels for separation membranes: from biological to biomimetic to synthetic

“…This is clearly manifested by the many unusual properties and behaviours that were reported in water nanochannels such as AQPs, graphene and CNTs. 9,40,46 Third and most importantly, these fundamental scientific discoveries provide innovative solutions for membrane science, especially against the recurring permeability-selectivity tradeoff commonly observed in polymeric membranes.…”

Universal dynamical onset in water at distinct material interfaces

“…Interfacial water is ubiquitous on Earth, playing a crucial role in biology, chemistry, physics, materials and environmental science. [1][2][3][4][5][6][7][8][9][10] The material surfaces, exhibiting a large degree of heterogeneity in their structure, chemistry and morphology, can signicantly perturb the structure and dynamics of the water located inside the hydration shell. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] One such consequence is the prevention of ice formation upon cooling, with interfacial water remaining in a liquid phase and mobile at temperatures much below 0 C. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] This non-freezing interfacial water imparts a great amount of exibility and mobility to the underlying substrate materials, such as protein, 4 DNA, 19…”

“…Interfacial water is ubiquitous on Earth, playing a crucial role in biology, chemistry, physics, materials and environmental science. 1–10 The material surfaces, exhibiting a large degree of heterogeneity in their structure, chemistry and morphology, can significantly perturb the structure and dynamics of the water located inside the hydration shell. 1–16 One such consequence is the prevention of ice formation upon cooling, with interfacial water remaining in a liquid phase and mobile at temperatures much below 0 °C.…”

“…1–10 The material surfaces, exhibiting a large degree of heterogeneity in their structure, chemistry and morphology, can significantly perturb the structure and dynamics of the water located inside the hydration shell. 1–16 One such consequence is the prevention of ice formation upon cooling, with interfacial water remaining in a liquid phase and mobile at temperatures much below 0 °C. 1–18 This non-freezing interfacial water imparts a great amount of flexibility and mobility to the underlying substrate materials, such as protein, 4 DNA, 19 RNA, 20 polymers 18 or ions, 21 to activate and ensure their functions at low temperatures.…”

Weakly Anisotropic Dielectric Properties of Water Droplets at the Nanoscale

“…Water confined in nanoscale environments exhibits many anomalous physical and chemical properties in comparison with bulk water. − In the past several decades, much effort in experiments and computer simulations has been dedicated to understand the intrinsic mechanism of these anomalies. With decreasing system size, the role of surface or interface becomes increasingly important.…”