Erratum: Corrigendum: Visualization of Surface Acoustic Waves in Thin Liquid Films

Arising from an interplay between capillary, acoustic and intermolecular forces, surface acoustic waves (SAWs) are observed to drive a unique and curious double flow reversal in the spreading of thin films. With a thickness at or less than the submicrometre viscous penetration depth, the film is seen to advance along the SAW propagation direction, and self-similarly over time t 1/4 in the inertial limit. At intermediate film thicknesses, beyond one-fourth the sound wavelength λ ℓ in the liquid, the spreading direction reverses, and the film propagates against the direction of the SAW propagation. The film reverses yet again, once its depth is further increased beyond one SAW wavelength. An unstable thickness region, between λ ℓ /8 and λ ℓ /4, exists from which regions of the film either rapidly grow in thickness to exceed λ ℓ /4 and move against the SAW propagation, consistent with the intermediate thickness films, whereas other regions decrease in thickness below λ ℓ /8 to conserve mass and move along the SAW propagation direction, consistent with the thin submicrometre films.

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Visualization of Surface Acoustic Waves in Thin Liquid Films

Scientific Reports ◽

10.1038/srep21980 ◽

2016 ◽

Vol 6 (1) ◽

Cited By ~ 20

Author(s):

R. W. Rambach ◽

J. Taiber ◽

C. M. L. Scheck ◽

C. Meyer ◽

J. Reboud ◽

...

Keyword(s):

Liquid Film ◽

Acoustic Waves ◽

Low Cost ◽

Thin Liquid Film ◽

Surface Acoustic Waves ◽

Liquid Films ◽

Theoretical Description ◽

Propagation Path ◽

Microfluidic Channels ◽

Potential Applications

Abstract We demonstrate that the propagation path of a surface acoustic wave (SAW), excited with an interdigitated transducer (IDT), can be visualized using a thin liquid film dispensed onto a lithium niobate (LiNbO3) substrate. The practical advantages of this visualization method are its rapid and simple implementation, with many potential applications including in characterising acoustic pumping within microfluidic channels. It also enables low-cost characterisation of IDT designs thereby allowing the determination of anisotropy and orientation of the piezoelectric substrate without the requirement for sophisticated and expensive equipment. Here, we show that the optical visibility of the sound path critically depends on the physical properties of the liquid film and identify heptane and methanol as most contrast rich solvents for visualization of SAW. We also provide a detailed theoretical description of this effect.

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Sculpting and Aerosolizing Pinned Liquid Films With Localized Acoustic Pressures of Surface Acoustic Waves

Volume 9: Micro- and Nano-Systems Engineering and Packaging, Parts A and B ◽

10.1115/imece2012-87249 ◽

2012 ◽

Author(s):

Daniel Taller ◽

Hsueh-Chia Chang ◽

David B. Go

Keyword(s):

Contact Angle ◽

Numerical Modeling ◽

Contact Line ◽

Acoustic Waves ◽

Acoustic Pressure ◽

Surface Acoustic Waves ◽

Liquid Films ◽

Solid Substrate ◽

Planar Surface ◽

Bulk Film

Due to viscous decay, a planar surface acoustic wave (SAW) diffracting from a solid substrate into a liquid film produces a time-averaged, exponentially decaying acoustic pressure in the film. We show that if the film is pinned against a bounding wall, the localized acoustic pressure generates a sequence of surface drops at the contact line, whose dimensions decay in the same exponential manner as the localized acoustic pressure. The undulating interfacial profile near the contact line also inherits this exponential decay, such that the averaged contact angle is exponentially small. The bulk film topology and the aerosolization mechanism are hence insensitive to the wettability of the surface but are controlled only by the localized acoustic pressure and the decaying undulations it produces at the contact line. The size distribution of surface drops is collapsed under the exponential scaling that depends only on the SAW decay rate and amplitude. Numerical modeling based on the Young-Laplace equation is used to model the liquid profile and to predict two aerosolization regimes.

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Characterization of RF Sputtered ZnO Piezoelectric Films Using Transmission Electron Microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100114050 ◽

1975 ◽

Vol 33 ◽

pp. 86-87

Author(s):

Kemining W. Yeh ◽

Richard S. Muller ◽

Wei-Kuo Wu ◽

Jack Washburn

Keyword(s):

Integrated Circuit ◽

Acoustic Waves ◽

New Technology ◽

Surface Acoustic Waves ◽

Electromechanical Properties ◽

Leading Role ◽

Saw Devices ◽

Transmission Electron ◽

High Degree

Considerable and continuing interest has been shown in the thin film transducer fabrication for surface acoustic waves (SAW) in the past few years. Due to the high degree of miniaturization, compatibility with silicon integrated circuit technology, simplicity and ease of design, this new technology has played an important role in the design of new devices for communications and signal processing. Among the commonly used piezoelectric thin films, ZnO generally yields superior electromechanical properties and is expected to play a leading role in the development of SAW devices.

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