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Probing hydrophilic interface of solid/liquid-water by nanoultrasonics.

Mante PA, Chen CC, Wen YC, Chen HY, Yang SC, Huang YR, Chen IJ, Chen YW, Gusev V, Chen MJ, Kuo JL, Sheu JK, Sun CK - Sci Rep (2014)

Bottom Line: To answer this question, a complete picture of the distribution of the water molecule structure and molecular interactions has to be obtained in a non-invasive way and on an ultrafast time scale.We developed a new experimental technique that extends the classical acoustic technique to the molecular level.Moreover, we discuss the effect of the interfacial water structure on the abnormal thermal transport properties of solid/liquid interfaces.

View Article: PubMed Central - PubMed

Affiliation: Department of Electrical Engineering and Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei 10617, Taiwan.

ABSTRACT
Despite the numerous devoted studies, water at solid interfaces remains puzzling. An ongoing debate concerns the nature of interfacial water at a hydrophilic surface, whether it is more solid-like, ice-like, or liquid-like. To answer this question, a complete picture of the distribution of the water molecule structure and molecular interactions has to be obtained in a non-invasive way and on an ultrafast time scale. We developed a new experimental technique that extends the classical acoustic technique to the molecular level. Using nanoacoustic waves with a femtosecond pulsewidth and an ångström resolution to noninvasively diagnose the hydration structure distribution at ambient solid/water interface, we performed a complete mapping of the viscoelastic properties and of the density in the whole interfacial water region at hydrophilic surfaces. Our results suggest that water in the interfacial region possesses mixed properties and that the different pictures obtained up to now can be unified. Moreover, we discuss the effect of the interfacial water structure on the abnormal thermal transport properties of solid/liquid interfaces.

No MeSH data available.


Related in: MedlinePlus

(a) Transient transmission changes (ΔT) obtained at a pump and probe wavelength of 400 nm with and without water. (b) Transient transmission changes induced by the acoustic waves reflected by the Al2O3/air or Al2O3/water after subtraction of the other contributions. Inset: Frequency dependent acoustic reflectivity obtained experimentally or using continuum elastic theory (CET).
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f2: (a) Transient transmission changes (ΔT) obtained at a pump and probe wavelength of 400 nm with and without water. (b) Transient transmission changes induced by the acoustic waves reflected by the Al2O3/air or Al2O3/water after subtraction of the other contributions. Inset: Frequency dependent acoustic reflectivity obtained experimentally or using continuum elastic theory (CET).

Mentions: We performed the nanoultrasonics experiments, first on the bare Al2O3 surface. Then, without moving the sample, we inject water and perform a second experiment. This technique allows to get rid of uncertainty due to the change of position22. Once the SQW absorbs the laser pulse, it launches an acoustic wave. This wave, then, propagates towards the surface, gets partially reflected or transmitted at the different interfaces, and is detected when it arrives back in the SQW. Figure 2(a) shows the transient transmission changes recorded with and without water at the Al2O3 surface.


Probing hydrophilic interface of solid/liquid-water by nanoultrasonics.

Mante PA, Chen CC, Wen YC, Chen HY, Yang SC, Huang YR, Chen IJ, Chen YW, Gusev V, Chen MJ, Kuo JL, Sheu JK, Sun CK - Sci Rep (2014)

(a) Transient transmission changes (ΔT) obtained at a pump and probe wavelength of 400 nm with and without water. (b) Transient transmission changes induced by the acoustic waves reflected by the Al2O3/air or Al2O3/water after subtraction of the other contributions. Inset: Frequency dependent acoustic reflectivity obtained experimentally or using continuum elastic theory (CET).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4150100&req=5

f2: (a) Transient transmission changes (ΔT) obtained at a pump and probe wavelength of 400 nm with and without water. (b) Transient transmission changes induced by the acoustic waves reflected by the Al2O3/air or Al2O3/water after subtraction of the other contributions. Inset: Frequency dependent acoustic reflectivity obtained experimentally or using continuum elastic theory (CET).
Mentions: We performed the nanoultrasonics experiments, first on the bare Al2O3 surface. Then, without moving the sample, we inject water and perform a second experiment. This technique allows to get rid of uncertainty due to the change of position22. Once the SQW absorbs the laser pulse, it launches an acoustic wave. This wave, then, propagates towards the surface, gets partially reflected or transmitted at the different interfaces, and is detected when it arrives back in the SQW. Figure 2(a) shows the transient transmission changes recorded with and without water at the Al2O3 surface.

Bottom Line: To answer this question, a complete picture of the distribution of the water molecule structure and molecular interactions has to be obtained in a non-invasive way and on an ultrafast time scale.We developed a new experimental technique that extends the classical acoustic technique to the molecular level.Moreover, we discuss the effect of the interfacial water structure on the abnormal thermal transport properties of solid/liquid interfaces.

View Article: PubMed Central - PubMed

Affiliation: Department of Electrical Engineering and Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei 10617, Taiwan.

ABSTRACT
Despite the numerous devoted studies, water at solid interfaces remains puzzling. An ongoing debate concerns the nature of interfacial water at a hydrophilic surface, whether it is more solid-like, ice-like, or liquid-like. To answer this question, a complete picture of the distribution of the water molecule structure and molecular interactions has to be obtained in a non-invasive way and on an ultrafast time scale. We developed a new experimental technique that extends the classical acoustic technique to the molecular level. Using nanoacoustic waves with a femtosecond pulsewidth and an ångström resolution to noninvasively diagnose the hydration structure distribution at ambient solid/water interface, we performed a complete mapping of the viscoelastic properties and of the density in the whole interfacial water region at hydrophilic surfaces. Our results suggest that water in the interfacial region possesses mixed properties and that the different pictures obtained up to now can be unified. Moreover, we discuss the effect of the interfacial water structure on the abnormal thermal transport properties of solid/liquid interfaces.

No MeSH data available.


Related in: MedlinePlus