Heterogeneous Nucleation on a Completely Wettable Substrate

Iwamatsu, Masao

doi:10.1002/9781118795620.ch3

Cited by 4 publications

(6 citation statements)

References 48 publications

(112 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Equation predicts that the formation of the critical nucleus is barrierless beyond that limit (region of complete wetting by ice in Figure ). On approaching this limit, the line tension of the ice–liquid–surface line, neglected in eq , would make an important contribution to the free energy barrier of nucleation and should be included in the CNT formulation. , Moreover, Iwamatsu has demonstrated that the existence of prewetting transitions leads to break down of CNT on approaching the complete wetting by ice limit, which results in a finite nucleation barrier for the heterogeneous nucleation of liquid from vapor . The conclusions of ref have not yet been generalized for the nucleation of a crystalline nucleus on a soft, wavy surface; but they would suggest that for surfaces with Δ G bind ≤ −2γ ice–water the freezing temperature approaches the equilibrium melting line but a finite barrier could still exist for heterogeneous nucleation.…”

Section: Results and Discussionmentioning

confidence: 99%

Ice Nucleation Efficiency of Hydroxylated Organic Surfaces Is Controlled by Their Structural Fluctuations and Mismatch to Ice

et al. 2017

View full text Add to dashboard Cite

Heterogeneous nucleation of ice induced by organic materials is of fundamental importance for climate, biology, and industry. Among organic ice-nucleating surfaces, monolayers of long chain alcohols are particularly effective, while monolayers of fatty acids are significantly less so. As these monolayers expose to water hydroxyl groups with an order that resembles the one in the basal plane of ice, it was proposed that lattice matching between ice and the surface controls their ice-nucleating efficiency. Organic monolayers are soft materials and display significant fluctuations. It has been conjectured that these fluctuations assist in the nucleation of ice. Here we use molecular dynamic simulations and laboratory experiments to investigate the relationship between the structure and fluctuations of hydroxylated organic surfaces and the temperature at which they nucleate ice. We find that these surfaces order interfacial water to form domains with ice-like order that are the birthplace of ice. Both mismatch and fluctuations decrease the size of the preordered domains and monotonously decrease the ice freezing temperature. The simulations indicate that fluctuations depress the freezing efficiency of monolayers of alcohols or acids to half the value predicted from lattice mismatch alone. The model captures the experimental trend in freezing efficiencies as a function of chain length and predicts that alcohols have higher freezing efficiency than acids of the same chain length. These trends are mostly controlled by the modulation of the structural mismatch to ice. We use classical nucleation theory to show that the freezing efficiencies of the monolayers are directly related to their free energy of binding to ice. This study provides a general framework to relate the equilibrium thermodynamics of ice binding to a surface and the nonequilibrium ice freezing temperature and suggests that these could be predicted from the structure of interfacial water.

show abstract

Section: Results and Discussionmentioning

confidence: 99%

Ice Nucleation Efficiency of Hydroxylated Organic Surfaces Is Controlled by Their Structural Fluctuations and Mismatch to Ice

et al. 2017

View full text Add to dashboard Cite

show abstract

“…However, it is possible to include long-ranged liquid-solid interaction by using the concept of disjoining pressure. Several studies 20,[44][45][46] have already examined the effect of the long-range force. However, most of those studies have focused on the case of complete wetting with the contact angle θ = 0…”

Section: Discussionmentioning

confidence: 99%

Line-tension-induced scenario of heterogeneous nucleation on a spherical substrate and in a spherical cavity

Iwamatsu

2015

The Journal of Chemical Physics

Self Cite

View full text Add to dashboard Cite

Line-tension-induced scenario of heterogeneous nucleation is studied for a lens-shaped nucleus with a finite contact angle nucleated on a spherical substrate and on the bottom of the wall of a spherical cavity. The effect of line tension on the free energy of a critical nucleus can be separated from the usual volume term. By comparing the free energy of a lens-shaped critical nucleus of a finite contact angle with that of a spherical nucleus, we find that a spherical nucleus may have a lower free energy than a lens-shaped nucleus when the line tension is positive and large, which is similar to the drying transition predicted by Widom [B. Widom, J. Phys. Chem. 99 2803(1995]. Then, the homogeneous nucleation rather than the heterogeneous nucleation will be favorable. Similarly, the free energy of a lens-shaped nucleus becomes negative when the line tension is negative and large. Then, the barrier-less nucleation with no thermal activation called athermal nucleation will be realized.

show abstract

“…Heterogeneous nucleation occurs when the binding free energy of the crystal (immersed in its melt) to the nucleating surface is negative (∆G bind < 0), while surface freezing requires a more stringent condition: that the binding free energy is less than minus twice the liquid-crystal surface tension of the alkane, (∆G bind < −2 γ xl ) [13,109]. This implies that there is a range of binding free energies for which heterogeneous nucleation can occur without surface freezing.…”

Section: Discussionmentioning

confidence: 99%

“…Heterogeneous nucleation can only be induced when cosα > −1, which implies that the binding free energy of the crystal nucleus to the surface is negative, ∆G bind = γ xs − (γ ls + γ xl ) < 0 ( Figure 6) [13]. Surface freezing can be considered a case of complete wetting of the surface by the crystal, which requires that ∆G bind < −2 γ xl ( Figure 6) if the line tension of the crystal-liquid-surface interface is neglected [13,109]. Heterogeneous nucleation at a surface can occur without surface freezing when −2 γ xl < ∆G bind < 0.…”

Section: The Sign and Magnitude Of The Binding Free Energy Of The Alkmentioning

confidence: 99%

See 1 more Smart Citation

Strength of Alkane–Fluid Attraction Determines the Interfacial Orientation of Liquid Alkanes and Their Crystallization through Heterogeneous or Homogeneous Mechanisms

Qiu

Molinero

2017

Crystals

View full text Add to dashboard Cite

Abstract:Alkanes are important building blocks of organics, polymers and biomolecules. The conditions that lead to ordering of alkanes at interfaces, and whether interfacial ordering of the molecules leads to heterogeneous crystal nucleation of alkanes or surface freezing, have not yet been elucidated. Here we use molecular simulations with the united-atom OPLS and PYS alkane models and the mW water model to determine what properties of the surface control the interfacial orientation of alkane molecules, and under which conditions interfacial ordering results in homogeneous or heterogeneous nucleation of alkane crystals, or surface freezing above the melting point. We find that liquid alkanes present a preference towards being perpendicular to the alkane-vapor interface and more parallel to the alkane-water interface. The orientational order in the liquid is short-ranged, decaying over~1 nm of the surface, and can be reversed by tuning the strength of the attractions between alkane and the molecules in the other fluid. We show that the strength of the alkane-fluid interaction also controls the mechanism of crystallization and the face of the alkane crystal exposed to the fluid: fluids that interact weakly with alkanes promote heterogeneous crystallization and result in crystals in which the alkane molecules orient perpendicular to the interface, while crystallization of alkanes in the presence of fluids, such as water, that interact more strongly with alkanes is homogeneous and results in crystals with the molecules oriented parallel to the interface. We conclude that the orientation of the alkanes at the crystal interfaces mirrors that in the liquid, albeit more pronounced and long-ranged. We show that the sign of the binding free energy of the alkane crystal to the surface, ∆G bind , determines whether the crystal nucleation is homogeneous (∆G bind ≥ 0) or heterogeneous (∆G bind < 0). Our analysis indicates that water does not promote heterogeneous crystallization of the alkanes because water stabilizes more the liquid than the crystal phase of the alkane, resulting in ∆G bind > 0. While ∆G bind < 0 suffices to produce heterogeneous nucleation, the condition for surface freezing is more stringent, ∆G bind < −2 γ xl , where γ xl is the surface tension of the liquid-crystal interface of alkanes. Surface freezing of alkanes is favored by their small value of γ xl . Our findings are of relevance to understanding surface freezing in alkanes and to develop strategies for controlling the assembly of chain-like molecules at fluid interfaces.

show abstract

Heterogeneous Nucleation on a Completely Wettable Substrate

Cited by 4 publications

References 48 publications

Ice Nucleation Efficiency of Hydroxylated Organic Surfaces Is Controlled by Their Structural Fluctuations and Mismatch to Ice

Ice Nucleation Efficiency of Hydroxylated Organic Surfaces Is Controlled by Their Structural Fluctuations and Mismatch to Ice

Line-tension-induced scenario of heterogeneous nucleation on a spherical substrate and in a spherical cavity

Strength of Alkane–Fluid Attraction Determines the Interfacial Orientation of Liquid Alkanes and Their Crystallization through Heterogeneous or Homogeneous Mechanisms

Contact Info

Product

Resources

About