The Contribution of Pyroelectricity of AgI Crystals to Ice Nucleation

Curland, Sofia; Meirzadeh, Elena; Cohen, Hagai; Ehre, David; Maier, Joachim; Lahav, Meir; Lubomirsky, Igor

doi:10.1002/anie.201802291

Cited by 15 publications

(15 citation statements)

References 30 publications

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“…AgI is well-known for its pyroelectricity and polymorphism related to superionic electrical conductivity . Also, ice nucleation on the surface of AgI is an exotic physical phenomenon. , Polymorphic behavior of the here-fabricated AgI thin-film was investigated by variable temperature out-of-plane XRD measurements at ambient pressure (Figure ).…”

Section: Resultsmentioning

confidence: 99%

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Chemistry at the Solid–Gas Interface: Direct Crystalline Thin-Film to Thin-Film Chemical Transformation

et al. 2021

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Single-crystal to single-crystal transformation is an elegant example of altering a crystalline solid-state of matter to a solid-state with a different chemical identity. Herein, we present an alluring example of thin-film to thin-film transformation of metal−organic to metal−halide by exploring chemistry at the solid−gas interface. Exposure of crystalline AgTCNQ (TCNQ = 7,7,8,8tetracyanoquinodimethane) thin-film to iodine (I 2 ) vapor and subsequent washing with chloroform (CHCl 3 ) generated crystalline AgI (silver iodide) thin-film. The chemical transformation AgTCNQ → AgI was so rapid that it took place within 2 min at ambient conditions. Reversible structural phase transition in the thin-film of AgI (β-phase ↔ α-phase) was further captured in variable temperature X-ray diffraction patterns, which appears promising for superionic conductivity and pyroelectricity applications.

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Section: Resultsmentioning

confidence: 99%

“…AgI is well-known for its pyroelectricity 29 and polymorphism related to superionic electrical conductivity. 30 Also, ice nucleation on the surface of AgI is an exotic physical phenomenon.…”

Section: Resultsmentioning

confidence: 99%

Chemistry at the Solid–Gas Interface: Direct Crystalline Thin-Film to Thin-Film Chemical Transformation

et al. 2021

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“…In addition, a proton-ordering process takes place within crevices of polar crystals that elevates the icing temperature of SCW. 2 − 4 , 14 , 21 , 25 …”

Section: Introductionmentioning

confidence: 99%

Chemical Nature of Heterogeneous Electrofreezing of Supercooled Water Revealed on Polar (Pyroelectric) Surfaces

et al. 2022

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Conspectus The ability to control the icing temperature of supercooled water (SCW) is of supreme importance in subfields of pure and applied sciences. The ice freezing of SCW can be influenced heterogeneously by electric effects, a process known as electrofreezing. This effect was first discovered during the 19th century; however, its mechanism is still under debate. In this Account we demonstrate, by capitalizing on the properties of polar crystals, that heterogeneous electrofreezing of SCW is a chemical process influenced by an electric field and specific ions. Polar crystals possess a net dipole moment. In addition, they are pyroelectric, displaying short-lived surface charges at their hemihedral faces at the two poles of the crystals as a result of temperature changes. Accordingly, during cooling or heating, an electric field is created, which is negated by the attraction of compensating charges from the environment. This process had an impact in the following experiments. The icing temperatures of SCW within crevices of polar crystals are higher in comparison to icing temperatures within crevices of nonpolar analogs. The role played by the electric effect was extricated from other effects by the performance of icing experiments on the surfaces of pyroelectric quasi-amorphous SrTiO 3 . During those studies it was found that on positively charged surfaces the icing temperature of SCW is elevated, whereas on negatively charged surfaces it is reduced. Following investigations discovered that the icing temperature of SCW is impacted by an ionic current created within a hydrated layer on top of hydrophilic faces residing parallel to the polar axes of the crystals. In the absence of such current on analogous hydrophobic surfaces, the pyroelectric effect does not influence the icing temperature of SCW. Those results implied that electrofreezing of SCW is a process influenced by specific compensating ions attracted by the pyroelectric field from the aqueous solution. When freezing experiments are performed in an open atmosphere, bicarbonate and hydronium ions, created by the dissolution of atmospheric CO 2 in water, influence the icing temperature. The bicarbonate ions, when attracted by positively charged pyroelectric surfaces, elevate the icing temperature, whereas their counterparts, hydronium ions, when attracted by the negatively charged surfaces reduce the icing temperature. Molecular dynamic simulations suggested that bicarbonate ions, concentrated within the near positively charged interfacial layer, self-assemble with water molecules to create stabilized slightly distorted “ice-like” hexagonal assemblies which mimic the hexagons of the crystals of ice. This occurs by replacing, within those ice-like hexagons, two hydrogen bonds of water by C–O bonds of the HCO 3 – ion. On the basis of these simulations, it was predicted and experimentally confirmed that other trigonal planar ions such as NO 3 ...

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“…[1][2][3] There are two types of ice nucleation, one is homogeneous ice nucleation and the other is heterogeneous ice nucleation. [4][5][6] Homogeneous ice nucleation does not require an external medium, but a lower environemnt temperature is needed, homogeneous ice nucleation would not occur when the temperature is higher than 235 K (about -38 ℃) [7][8][9][10] . Heterogeneous ice nucleation can occur at a warmer temperature, but heterogeneous ice nucleation requires the participation of external medium.…”

Section: Introductionmentioning

confidence: 99%

Effect of interfacial dipole on heterogeneous ice nucleation

Lu¹,

Xu²,

Wu³

et al. 2021

J. Phys.: Condens. Matter

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Heterogeneous ice nucleation is one of the most common and important process in the physical environment. AgI has been proved to be an effective ice nucleating agent in the process of ice nucleation. However, the microscopic mechanism of AgI in heterogeneous ice nucleation has not been fully understood.Molecular dynamics simulations are applied to investigate the ability of which kinds of  -AgI substrate can promote ice nucleation by changing the dipole of  -AgI on the substrate, we conclude that the dipole of  -AgI on the substrate can affect the conformation of ice nucleation. The surface ions with positive charge on the substrate may promote ice nucleation, while there is no ice nucleation founded on the surface ions with negative charge.  -AgI substrates affect ice nucleation through adjust the orientations of water molecules near the surfaces.

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The Contribution of Pyroelectricity of AgI Crystals to Ice Nucleation

Cited by 15 publications

References 30 publications

Chemistry at the Solid–Gas Interface: Direct Crystalline Thin-Film to Thin-Film Chemical Transformation

Chemistry at the Solid–Gas Interface: Direct Crystalline Thin-Film to Thin-Film Chemical Transformation

Chemical Nature of Heterogeneous Electrofreezing of Supercooled Water Revealed on Polar (Pyroelectric) Surfaces

Effect of interfacial dipole on heterogeneous ice nucleation

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