Hypothesis: The coalescence of droplets with liquid-gas interfaces of different surface tensions is common in nature and industrial applications, where the Marangoni-driven film spreading is an essential process. Unlike immiscible fluids governed by triple contact line dynamics, the mixing between two miscible fluids strongly couples with the film spreading process, which are expected to manifest distinct power-law relations for the temporal increase in the film radius.
Experiments: We experimentally investigate the Marangoni-driven film spreading phenomenon for a droplet with lower surface tension dropping onto a miscible, thin liquid layer. The temporal growth of the film radius was detected by using a novel deep convolutional neural network, the U-net method. Scaling analysis was performed to interpret the spreading dynamics of the film.
Findings: We find that the film radius exhibits a three-stage power-law relation over time, with the exponent varying from 1/2 to 1/8, and back to 1/2. The diffusion-affected Marangoni stresses in these three stages were derived, and two estimations of viscous stress were considered. Through estimating and balancing the viscous stress with the Marangoni stress, the three-stage power-law relation was derived and validated.
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http://dx.doi.org/10.1016/j.jcis.2023.12.092 | DOI Listing |
Ophthalmic Physiol Opt
January 2025
School of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, Australia.
Purpose: To assess the repeatability of lipid layer thickness (LLT) measurement using the LipiView® interferometer after daily disposable contact lens (CL) wear and correlation with ocular comfort in soft contact lens wearers.
Methods: A prospective study was conducted over two consecutive months, wherein CL wearers (n = 20) wore either Somofilcon A or Verofilcon A daily disposable CLs in a crossover design, switching lenses after 1 month. The pre-corneal tear film LLT was measured at the end of each month after CLs had been worn for at least 6 h.
Adv Sci (Weinh)
January 2025
SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon, 16419, South Korea.
Molecular diagnosis limitations, including complex treatment processes, low cost-effectiveness, and operator-dependent low reproducibility, interrupt the timely prevention of disease spread and the development of medical devices for home and outdoor uses. A newly fabricated gold nanopillar array-based film is presented for superior photothermal energy conversion. Magnifying the metal film surface-to-volume ratio increases the photothermal energy conversion efficiency, resulting in a swift reduction in the gene amplification reaction time.
View Article and Find Full Text PDFSci Technol Adv Mater
January 2025
Magnetic Functional Device Group, Research Center for Magnetic and Spintronic Materials (CMSM), National Institute for Materials Science (NIMS), Tsukuba, Japan.
We demonstrate high-throughput evaluation of the half-metallicity of CoMnSi Heusler alloys by spin-integrated hard X-ray photoelectron spectroscopy (HAXPES) of composition-spread films performed with high-brilliance synchrotron radiation at NanoTerasu, which identifies the optimum composition showing the best half-metallicity. Co Mn Si composition-spread thin films for = 10-40% with a thickness of 30 nm are fabricated on MgO(100) substrates using combinatorial sputtering technique. The 2-ordering and (001)-oriented epitaxial growth of CoMnSi are confirmed by X-ray diffraction for = 18-40%.
View Article and Find Full Text PDFAdv Mater
January 2025
College of Chemistry and Chemical Engineering/Film Energy Chemistry for Jiangxi Provincial Key Laboratory (FEC), Nanchang University, 999 Xuefu Avenue, Nanchang, 330031, China.
The coffee-ring effect, caused by uneven deposition of colloidal particles in perovskite precursor solutions, leads to poor uniformity in perovskite films prepared through large-area printing. In this work, the surface of SnO is roughened to construct a Wenzel model, successfully achieving a super-hydrophilic interface. This modification significantly accelerates the spreading of the perovskite precursor solution, reducing the response delay time of perovskite colloidal particles during the printing process.
View Article and Find Full Text PDFCornea
November 2024
Department of Ophthalmology and Visual Sciences, University of Louisville, Louisville, KY.
Purpose: To visualize the behavior of perfluorohexyloctane (PFHO), an eye drop to treat dry eye disease (DED), on the surface of saline in vitro and on the human ocular surface using infrared emissivity.
Methods: Emissivity videos were used to measure the spreading and disappearance rates of PFHO on saline (with and without mucin for spreading rate) and layered over a 125 nm film of meibum on the surface of saline using a TearView camera. Ocular surface emissivity was videoed in a volunteer without DED before and after instillation of 1 drop of PFHO.
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