Polarization of water molecules at a charged interface. Second harmonic studies of charged monolayers at the air/water interface

Zhao, Xiaolin; Ong, Shaowei; Eisenthal, Kenneth B.

doi:10.1016/0009-2614(93)90041-x

Cited by 156 publications

(258 citation statements)

References 25 publications

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“…8 Dielectric anomalies might be anticipated near the critical point of water due to ferroelectric contributions from the water itself, 23,24 or interface polarization contributions from the water [25][26][27][28] induced by the surrounding PVDF-TrFE. The ''anomaly'' in the capacitance versus temperature that we have observed is probably dynamic and does not necessarily signify any water-related transition in the film.…”

Section: Figmentioning

confidence: 99%

Water absorption and dielectric changes in crystalline poly(vinylidene fluoride-trifluoroethylene) copolymer films

Jacobson

Rosa

Othon

et al. 2004

Applied Physics Letters

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Crystalline Langmuir–Blodgett copolymer films of vinylidene fluoride with trifluoroethylene (70%:30% and 80%:20%) absorb water. Water absorption is accompanied by film swelling, as indicated by an increase in lattice spacing, sometimes by as much as 5%. This water absorption, between 0 and 40 °C, is a result of intercalation or occupation of interstitial sites between the layers of the film, not just water molecules filling voids and defect sites alone. An increase in the film capacitance is observed, although the polymer chains retain all trans configuration of the ferroelectric phase.

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Section: Figmentioning

confidence: 99%

Water absorption and dielectric changes in crystalline poly(vinylidene fluoride-trifluoroethylene) copolymer films

Jacobson

Rosa

Othon

et al. 2004

Applied Physics Letters

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“…The signal response relates to the overall arrangements of the interfacial entities (Fordyce et al, 2001;Goh et al, 1988;Luca et al, 1995) and is proportional to the incident field and the second-order nonlinear susceptibility χ (2) of the interface. When the interface is charged, due to this charge, the static electric field can induce a third-order nonlinear polarization due to the contribution of the thirdorder nonlinear susceptibility χ (3) of the solution (Ong et al, 1992;Zhao et al, 1993). In this work, the contribution of χ (3) to the total SHG signal has been ignored because there was no significant change in the interface charge with temperature.…”

Section: Introductionmentioning

confidence: 99%

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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“…In previous experiments, we have observed a similar effect from the intrinsic charges at the interfaces with no external field applied. 12,[32][33][34] The electric field due to the surface charges polarizes the solvent molecules, i.e., water in the present studies, resulting in the breakdown of the centrosymmetry of the bulk solution (Scheme 3). When there are no surface charges, i.e., in the absence of a static field, the water molecules beyond the first few layers would be randomly oriented and consequently would not contribute to the SHG signal.…”

Section: B Shg Due To the Surface Charges On Clay Particlesmentioning

confidence: 83%

Probing the Interface of Microscopic Clay Particles in Aqueous Solution by Second Harmonic Generation

Yan

Eisenthal

1999

J. Phys. Chem. B

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Second harmonic generation (SHG) is applied for the first time to study the surfaces of clay particles. An SHG signal was detected from an aqueous suspension of disk-shaped montmorillonite clay particles of 0.5 µm diameter and 0.01 µm thickness. The origin of the SHG signal is the polarization of water molecules by surface charges located in the edge region of the clay particles. On addition of the organic molecule 4-(2-pyridylazo)resorcinol (PR) to the clay aqueous suspension, a strong SHG signal originating from the PR molecules adsorbed onto the edge surfaces of the clay particles was obtained. The PR adsorbed on the basal planes do not contribute to the SHG signal because of cancellation effects. These experimental results demonstrate the applicability of the SHG method for studying molecular adsorption and the electrostatic properties of clay particles.

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Polarization of water molecules at a charged interface. Second harmonic studies of charged monolayers at the air/water interface

Cited by 156 publications

References 25 publications

Water absorption and dielectric changes in crystalline poly(vinylidene fluoride-trifluoroethylene) copolymer films

Water absorption and dielectric changes in crystalline poly(vinylidene fluoride-trifluoroethylene) copolymer films

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

Probing the Interface of Microscopic Clay Particles in Aqueous Solution by Second Harmonic Generation

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