Topic
Sessile drop technique
About: Sessile drop technique is a research topic. Over the lifetime, 2827 publications have been published within this topic receiving 68943 citations.
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TL;DR: High-resolution patterns of grooves have been made in poly(methyl methacrylate) films, PMMA, by an electron-beam microlithographic process and contact guidance is induced by the topography of the surface and not by the alternation of zones with different physico-chemical properties.
54 citations
TL;DR: Compared the deposit patterns resulting from the evaporation of water droplets containing silica nanoparticles on hydrophobic surfaces orientated in the sessile or pendant configuration, the well known coffee ring pattern surrounding a thin nanoparticle layer was formed.
54 citations
TL;DR: In this article, Bostwick et al. performed a linear stability analysis that predicts how inviscid drop spectra depend on the base state geometry, i.e., spherical caps characterized by their flatness or fraction of the full sphere.
Abstract: High-speed images of driven sessile water drops recorded under frequency scans are analysed for resonance peaks, resonance bands and hysteresis of characteristic modes. Visual mode recognition using back-lit surface distortion enables modes to be associated with frequencies, aided by the identifications in Part 1 (Bostwick & Steen, J. Fluid Mech., vol. 760, 2014, pp. 5‐38). Part 1 is a linear stability analysis that predicts how inviscid drop spectra depend on base state geometry. Theoretically, the base states are spherical caps characterized by their ‘flatness’ or fraction of the full sphere. Experimentally, quiescent shapes are controlled by pinning the drop at a circular contact line on the flat substrate and varying the drop volume. The response frequencies of the resonating drop are compared with Part 1 predictions. Agreement with theory is generally good but does deteriorate for flatter drops and higher modes. The measured frequency bands agree better with an extended model, introduced here, that accounts for forcing and weak viscous effects using viscous potential flow. As the flatness varies, regions are predicted where modal frequencies cross and where the spectra crowd. Frequency crossings and spectral crowding favour interaction of modes. Modal interactions of two kinds are documented, called ‘mixing’ and ‘competing’. Mixed modes are two pure modes superposed with little evidence of hysteresis. In contrast, modal competition involves hysteresis whereby one or the other mode disappears depending on the scan direction. Perhaps surprisingly, a linear inviscid irrotational theory provides a useful framework for understanding observations of forced sessile drop oscillations.
54 citations
TL;DR: In this paper, a sessile drop technique was used to study the wetting and spreading characteristics of ZrB2 in contact with liquid Cu, Ag, and Au under a vacuum.
Abstract: Wetting and spreading experiments on ZrB2 in contact with liquid Cu, Ag and Au have been performed by the sessile drop technique under a vacuum. The wetting and spreading characteristics and the interfacial reactions are discussed as a function of time and of the metal involved. The interfacial morphologies, analysed by optical microscopy, SEM and EDS show the presence of regular interfaces without macroscopic reaction layers. Gold, to a very large extent and copper are shown to give rise to extensive penetration along grain-boundaries, whereas silver neither wets nor penetrates. Interfacial diffusion/dissolution is taken into account and the consequent changes in liquid metal surface tension and wetting behaviours have been evaluated by means of thermodynamic calculations. Moreover, interfacial energetics at the atomistic level has been investigated by means of pseudopotential-based Density Functional Theory (DFT) technique. It is shown how the calculation of the ideal work of separation on the specific transition metal borides-molten metal systems can be used to interpret the wetting behaviour. Moreover, the dependence of the adhesion behaviour on the electronic structure at the interface and on the interface epitaxy and composition is also briefly discussed.
54 citations
TL;DR: In this article, the surface free energies of asphalt and aggregate were characterized on the basis of the Owens-Wendt's theory, and it was found that the sessile drop technique is a convenient way to determine the static contact angle.
Abstract: Surface free energy is an important parameter to determine the work of adhesion between the asphalt binder and the aggregate, which is related to the moisture damage of asphalt mixture. In this study, the sessile drop technique was performed to obtain the contact angle between asphalt/aggregate and different probe liquids. The surface free energies of asphalt and aggregate were characterized on the basis of the Owens-Wendt’s theory. It was found that the sessile drop technique is a convenient way to determine the static contact angle. A test procedure was developed to offer a clear method to prepare the sample and measure the contact angle. The surface free energy of aggregate determined in this study was found to be smaller than that measured in other techniques because of equilibrium spreading pressure. The work of adhesion calculated from surface free energy can be utilized to choose the best combination of asphalt and aggregate, which can work as a reference in the selection of materials. Meanwhile, it was found that for the same aggregate, the pull-off strength and the work of adhesion of each asphalt-aggregate have the same trend of ranking.
54 citations