Surface Charge Affects the Structure of Interfacial Ice

Anim-Danso, Emmanuel; Zhang, Yu; Dhinojwala, Ali

doi:10.1021/acs.jpcc.5b08371

Cited by 45 publications

(59 citation statements)

References 64 publications

(131 reference statements)

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“…Further cooling of the sample in contact with liquid bulk causes water to freeze by immersion freezing (IF). The observed IF temperatures for IF1, IF2, and IF3 are similar and center around −11 ± 1 • C, which is within the range of IF temperatures observed for the freezing of bulk water in contact with the surface of mica in former studies (Abdelmonem et al, 2015;Anim-Danso et al, 2016). IF produced a transient ice phase with an SHG intensity higher than that of the interfacial water of the bulk liquid.…”

Section: Resultssupporting

confidence: 84%

Direct molecular-level characterization of different heterogeneous freezing modes on mica – Part 1

Abdelmonem

2017

Atmos. Chem. Phys.

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Abstract. The mechanisms behind heterogeneous ice nucleation are of fundamental importance to the prediction of the occurrence and properties of many cloud types, which influence climate and precipitation. Aerosol particles act as cloud condensation and freezing nuclei. The surface-water interaction of an ice nucleation particle plays a major, not well explored, role in its ice nucleation ability. This paper presents a real-time molecular-level comparison of different freezing modes on the surface of an atmospherically relevant mineral surface (mica) under varying supersaturation conditions using second-harmonic generation spectroscopy. Two sub-deposition nucleation modes were identified (one-and two-stage freezing). The nonlinear signal at the water-mica interface was found to drop following the formation of a thin film on the surface regardless of (1) the formed phase (liquid or ice) and (2) the freezing path (one or two step), indicating similar molecular structuring. The results also revealed a transient phase of ice at water-mica interfaces during freezing, which has a lifetime of around 1 min. Such information will have a significant impact on climate change, weather modification, and the tracing of water in hydrosphere studies.

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Section: Resultssupporting

confidence: 84%

Direct molecular-level characterization of different heterogeneous freezing modes on mica – Part 1

Abdelmonem

2017

Atmos. Chem. Phys.

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“…The significant increase in SF intensity upon melting is not unique to silica, as a similar behaviour has been recently reported to occur with another negatively charged surface, specifically muscovite mica. 57 Finally, we note that as the PML becomes thicker it is also likely that SF signal can be generated from the retreating ice/PML interface. We speculate that this could be origin of the 3050 cm À1 feature resolved in the À0.3 1C spectra (Fig.…”

Section: Vsf Spectroscopy: Pml Onset and Molecular Insightmentioning

confidence: 83%

The premolten layer of ice next to a hydrophilic solid surface: correlating adhesion with molecular properties

Liljeblad

Furó

Tyrode

2017

Phys. Chem. Chem. Phys.

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In order to establish the potential correlation between the macroscopic ice adhesion and the molecular properties of the premolten layer (PML), the adhesion strength between ice and hydrophilic silica has been measured as a function of temperature. In addition, temperature-dependent molecular properties have been determined using techniques that are sensitive to different aspects of the PML, specifically total internal reflection (TIR) Raman, vibrational sum frequency (VSFS) and NMR spectroscopies. The ice shear adhesion strength was observed to increase linearly with decreasing temperature until -25 °C, where a plateau marked the adhesive strength having reached the cohesive strength of ice. Interestingly, at temperatures higher than -20 °C the ice samples slid on smooth (R < 0.4 nm) silica surfaces. This sliding behavior was not observed on rougher silica surfaces (R ∼ 6 nm). By varying the penetration depth of the evanescent field, TIR Raman was used to establish an upper limit to the thickness of the PML in contact with silica (<3 nm even at -0.3 K below the bulk melting temperature). Additional quantitative determination of the temperature-dependent thickness of the PML was obtained from H NMR measurements in mesoporous silica particles. Finally, the inherently surface specific technique, VSFS, which probed changes in the hydrogen bond environment, indicated at approximately -25 °C the onset of PML, followed by a marked structural change occurring just a fraction of a degree below the melting temperature. Jointly, the experimental approaches link, strongly and consistently, ice adhesion to the PML properties. Specifically, it is inferred that the premolten layer facilitates sliding and contributes to the observed friction behavior, provided its thickness is comparable to the surface roughness of the underlying silica substrate.

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“…Though, it has been questioned whether this process actually occurs, or whether ice forms by pore condensation and freezing (PCF), after stabilizing water in pores by an inverse Kelvin effect (Marcolli, 2014). The most important IN mechanisms in mixed-phase clouds are viewed to be immersion and condensation freezing (Hoose et al, 2008;Ansmann et al, 2009;Twohy et al, 2010;de Boer et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Ice nucleation activity of silicates and aluminosilicates in pure water and aqueous solutions – Part 3: Aluminosilicates

2019

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Abstract. Aluminosilicates and quartz constitute the majority of airborne mineral dust. Despite similarities in structures and surfaces they differ greatly in terms of their ice nucleation (IN) efficiency. Here, we show that determining factors for their IN activity include surface ion exchange, NH3 or NH4+ adsorption, and surface degradation due to the slow dissolution of the minerals. We performed immersion freezing experiments with the (Na-Ca)-feldspar andesine, the K-feldspar sanidine, the clay mineral kaolinite, the micas muscovite and biotite, and gibbsite and compare their IN efficiencies with those of the previously characterized K-feldspar microcline and quartz. Samples were suspended in pure water as well as in aqueous solutions of NH3, (NH4)2SO4, NH4Cl and Na2SO4, with solute concentrations corresponding to water activities aw equal to 0.88–1.0. Using differential scanning calorimetry (DSC) on emulsified micron-sized droplets, we derived onset temperatures of heterogeneous (Thet) and homogeneous (Thom) freezing as well as heterogeneously frozen water volume fractions (Fhet). Suspensions in pure water of andesine, sanidine and kaolinite yield Thet equal to 242.8, 241.2 and 240.3 K, respectively, while no discernable heterogeneous freezing signal is present in the case of the micas or gibbsite (i.e., Thet≈Thom≈237.0 K). The presence of NH3 and/or NH4+ salts as solutes has distinct effects on the IN efficiency of most of the investigated minerals. When feldspars and kaolinite are suspended in very dilute solutions of NH3 or NH4+ salts, Thet shifts to higher temperatures (by 2.6–7.0 K compared to the pure water suspension). Even micas and gibbsite develop weak heterogeneous freezing activities in ammonia solutions. Conversely, suspensions containing Na2SO4 cause the Thet of feldspars to clearly fall below the water-activity-based immersion freezing description (Δaw= const.) even in very dilute Na2SO4 solutions, while Thet of kaolinite follows the Δaw= constant curve. The water activity determines how the freezing temperature is affected by solute concentration alone, i.e., if the surface properties of the ice nucleating particles are not affected by the solute. Therefore, the complex behavior of the IN activities can only be explained in terms of solute-surface-specific processes. We suggest that the immediate exchange of the native cations (K+, Na+, Ca2+) with protons, when feldspars are immersed in water, is a prerequisite for their high IN efficiency. On the other hand, excess cations from dissolved alkali salts prevent surface protonation, thus explaining the decreased IN activity in such solutions. In kaolinite, the lack of exchangeable cations in the crystal lattice explains why the IN activity is insensitive to the presence of alkali salts (Δaw= const.). We hypothesize that adsorption of NH3 and NH4+ on the feldspar surface rather than ion exchange is the main reason for the anomalous increased Thet in dilute solutions of NH3 or NH4+ salts. This is supported by the response of kaolinite to NH3 or NH4+, despite lacking exchangeable ions. Finally, the dissolution of feldspars in water or solutions leads to depletion of Al and formation of an amorphous layer enriched in Si. This hampers the IN activity of andesine the most, followed by sanidine, then eventually microcline, the least soluble feldspar.

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Surface Charge Affects the Structure of Interfacial Ice

Cited by 45 publications

References 64 publications

Direct molecular-level characterization of different heterogeneous freezing modes on mica – Part 1

Direct molecular-level characterization of different heterogeneous freezing modes on mica – Part 1

The premolten layer of ice next to a hydrophilic solid surface: correlating adhesion with molecular properties

Ice nucleation activity of silicates and aluminosilicates in pure water and aqueous solutions – Part 3: Aluminosilicates

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