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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01 Jan 2018
TL;DR: It is concluded that larger aggregates of particles are found near the edge of the drop at the expense of the smaller ones in the absence of adhesion, which is in agreement with a previous experiment when accounting for the corresponding DLVO forces.
Abstract: Electrical double layer and van der Waals (DLVO) forces are known to determine the morphology of the deposit of colloidal particles following the evaporation of the carrier liquid. It is assumed that the adsorption of particles to the solid substrate and their coagulation in the liquid are the mechanisms connecting DLVO forces to the morphology of the deposit. We use theory to test this assertion. We model the deposition of particles from a volatile drop while accounting for the contribution of adhesion and coagulation. The rate of both mechanisms is connected to DLVO forces via the interaction-force boundary layer and the Smoluchowski theorems, respectively. We present analytical solutions for the morphology of the deposit, accounting for particle adsorption and pair-limited coagulation, and a corresponding numerical analysis for the case where particle adhesion and coagulation are concurrent. We conclude that larger aggregates of particles are found near the edge of the drop at the expense of the smaller ones in the absence of adhesion. The adhesion of particles to the substrate smears the deposit, rendering large aggregates to appear near the center of the drop. The analysis is in agreement with a previous experiment when accounting for the corresponding DLVO forces.
31 citations
TL;DR: The rate of surface photo-oxidation and changes in polarity of the surfaces of artists' alkyd paint films were studied by a rapid and novel approach using sessile drop contact angle measurements as discussed by the authors.
31 citations
TL;DR: In this article, the authors present results obtained from a parabolic flight campaign regarding ethanol sessile drop evaporation under reduced gravity conditions using a syringe pump by means of injection through a PTFE (polytetrafluoroethylene) substrate.
Abstract: We present in this paper results obtained from a parabolic flight campaign regarding ethanol sessile drop evaporation under reduced gravity conditions. Drops are created using a syringe pump by means of injection through a PTFE (polytetrafluoroethylene) substrate. The drops are recorded using a video camera and an infrared camera to observe the thermal motion inside the drop and on the heating substrate. The experimental set-up presented in this paper enables the simultaneous visualization and access to the heat flux density that is transferred to the drop using a heat flux meter placed between the heating block and the PTFE substrate. We evidence original thermal spreading phenomena during the ethanol drop creation on a heated PTFE substrate. The drop exhibits specific behaviour which is discussed here. This work is performed in the frame of a French-Chinese collaboration (project IMPACHT) for future experiments in a Chinese scientific satellite.
31 citations
TL;DR: The electron—donor properties of the materials were positively correlated with the adhesion of S. aureus but not with E. coli, in agreement with the results of the MATS (Microbial Adhesion To Solvents) test performed on the two bacteria.
Abstract: In recent years, polysaccharide-based films have been developed for many applications. Some of these are in the pharmaceutical industry, where the adhesion of microorganisms to surfaces is a concern. After adhesion of a microorganism to a solid surface has taken place, the subsequent biofilm formed can act as a vehicle for spreading infections. The aim of this study is to compare the bacterial adhesion of E. coli and S. aureus from a contaminated solid model (Tryptone Soya Agar) to a range of polysaccharide-based films. These polysaccharide-based films consist of different natural starches (potato, cassava, wheat, pea and rice) and synthetic polymers hydroxyl-propyl cellulose (HPC) and carboxyl methyl cellulose (CMC)). The surface energy parameters of the films were calculated from the contact angle measurements by the sessile drop method. Apolar and polar liquids (water, formamide and hexadecane) and the Lifshitz-Van der Waals/acid-base (LW/AB) approach were used according to the method of Van Oss, Chaundhury and Good. The surface properties of the films were also correlated to the microbial adhesion. This indicated that, for both E. coli and S. aureus, the surface roughness did not affect the microbial adhesion. Only g\textS\textAB SABhad any correlation with the microbial adhesion and g\textS\textLW SLWwas almost constant for all the various polysaccharide films tested. In addition, the electron—donor properties of the materials, exhibited via g\textS + +S, were positively correlated with the adhesion of S. aureus but not with E. coli. This was in agreement with the results of the MATS (Microbial Adhesion To Solvents) test performed on the two bacteria. This revealed that only S. aureus presented an electron—acceptor characteristic.
31 citations
TL;DR: In this article, the wettability of different nanotextured metallic glass surfaces is investigated using sessile drop technique using a distilled water droplet, and it is demonstrated that hydrophilic-hydrophobic nature of the metallic glass surface can be controlled through nanotopography.
31 citations