Special Discussions of The Faraday Society最新文献

{"title":"Contact between a gas bubble and a solid surface and froth flotation","authors":"A. Scheludko, Sl. Tschaljowska, A. Fabrikant","doi":"10.1039/SD9700100112","DOIUrl":"https://doi.org/10.1039/SD9700100112","url":null,"abstract":"The process of formation of the contact silica surface/air when pressing a liquid meniscus on to the solid/liquid interface is investigated. The kinetics of expansion of the contact area and the final states characterized by contact angles in both directions (by spreading and withdrawing of the contact) are examined. Preliminary data about the effect of surfactants on the velocity of expansion of the contact and on the contact angle and its hysteresis are presented. The new methods applied in the investigations are described. The results are compared with flotation experiment data.","PeriodicalId":341426,"journal":{"name":"Special Discussions of The Faraday Society","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124671783","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Measurement of forces between colloidal particles","authors":"L. Barclay, R. Ottewill","doi":"10.1039/SD9700100138","DOIUrl":"https://doi.org/10.1039/SD9700100138","url":null,"abstract":"Apparatus has been constructed for the measurement of the pressure created by disperse systems as a function of the volume concentration of the disperse phase. Experiments with sodium montmorillonite as the colloidal system have enabled the force to be obtained as a function of the distance between the plates down to distances of the order of 10 A. The results have been compared with those expected theoretically on the basis of the DLVO theory. The forces obtained at distances of less than 50 A are much greater than those predicted by the theory and the additional force appears to arise from solvation effects in the thin liquid film between the particles. This has been confirmed by carrying out measurements in the presence of a non-ionic surface-active agent, a known stabilizing agent, where the repulsive forces due to solvation are enhanced.","PeriodicalId":341426,"journal":{"name":"Special Discussions of The Faraday Society","volume":"91 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126271332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Boundary layers between silver iodide and aqueous solutions at low temperatures","authors":"B. Vincent, J. Lyklema","doi":"10.1039/SD9700100148","DOIUrl":"https://doi.org/10.1039/SD9700100148","url":null,"abstract":"Potentiometric titration studies have been made on AgI suspensions over the temperature range 0–20°C, in the presence of LiNO3, KNO3 and RbNO3. Points-of-zero-charge (p.z.c.), double-layer capacities and surface entropy data, derived from the titration results, indicate an increase in water “structure”, as the temperature tends to 0°C, around the p.z.c. region, and particularly on the positive side. For strongly negatively charged surfaces the charge ordering effect on the dipoles tends to break down this structuring. The results of flocculation studies on AgI sols have been combined with the titration data to yield information about changes in double layer parameters with temperature. The results fit the suggestions made regarding changes in water structuring at the interface.","PeriodicalId":341426,"journal":{"name":"Special Discussions of The Faraday Society","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121580820","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Smectic model for liquid films on solid surfaces. Part 1.—Application to monolayer boundary lubrication","authors":"E. Drauglis, A. Lucas, C. Allen","doi":"10.1039/SD9700100251","DOIUrl":"https://doi.org/10.1039/SD9700100251","url":null,"abstract":"A qualitative theory of films of hydrocarbon solutions of fatty acids described in a previous publication correlates many experimental data. According to this theory the fatty acid molecules and solvent molecules are arranged in layered structures similar to those in smectic mesophases. A simplified method for calculating the attractive energy between two such layers is described. The fatty acid molecules are assumed to behave as hard rods of constant electric polarizability and diamagnetic susceptibility. A potential describing the interaction between two rods is derived and used in a lattice sum calculation to compute the total energy of interaction of two layers as a function of average separation of molecules within a layer, relative position of the two layers and the distance between layers. Calculation of frictional force and coefficient of friction by means of this model show good agreement with a similar calculation of Cameron if the proper assumption about the relative magnitude of energy as a function of relative position is made.","PeriodicalId":341426,"journal":{"name":"Special Discussions of The Faraday Society","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123906594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Interfacial energies of clean mica and of monomolecular films of fatty acids deposited on mica, in aqueous and non-aqueous media","authors":"A. Bailey, A. G. Price, S. M. Kay","doi":"10.1039/SD9700100118","DOIUrl":"https://doi.org/10.1039/SD9700100118","url":null,"abstract":"The influence of a variety of media on solid/fluid interfacial energies has been measured by a cleavage technique. The solid used was mica, chosen because of its near perfect cleavage and ideal bulk properties. Solid/vapour and solid/liquid interfacial energies, γSV and γSL, were measured by cleaving specimens in the form of strips, first, in an atmosphere of the vapour and then with the specimens completely immersed in the corresponding liquid. Samples of mica coated with monomolecular films of fatty acids were constructed in such a way that separation took place between the oppositely oriented films. Polar and non-polar liquids and vapours were used in these experiments. The results allow an investigation into the validity of Young's equation for contact angles which are zero or positive. For well-behaved systems in which no adsorption takes place during the cleavage, the relation is valid. For fatty acid films in an aqueous environment, it is necessary to introduce an additional term into the relation to preserve the equality, thus γSL=γSV–γLV cos θ+γH·. The energy γH has been associated with entropic effects occurring in the liquid phase. Its existence shows that there are measurable anisotropies in the water. The results can be explained if a single layer of the water in the immediate vicinity of the hydrophobic interface, is assumed to become preferentially oriented.Model-building experiments have been used to estimate the number of water molecules involved in the interaction and a value of 213 cal/mol of oriented water was obtained for the energy involved. This allows one to predict values for the free energy of solution of small hydrophobic molecules in water, which are in good agreement with those of Frank and Evans. The effect disappears in a concentrated solution of urea indicating that the structure of the liquid near the interface is, in this case, effectively the same as it is in bulk, i.e., the urea has caused a breakdown in the ordered structure in the neighbourhood of the interface. This is consistent with current views of the denaturant action of urea on proteins and other bimolecules.","PeriodicalId":341426,"journal":{"name":"Special Discussions of The Faraday Society","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122252910","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bursting of soap films. Part 4.—The behaviour of ions on a crowded surface","authors":"G. Frens, K. J. Mysels, B. Vijayendran","doi":"10.1039/SD9700100012","DOIUrl":"https://doi.org/10.1039/SD9700100012","url":null,"abstract":"The growing hole of a bursting soap film is preceded by an aureole of accelerating, contracting, and thickening film. Measurements of the cross-sectional profile of such aureoles are reported and provide the basis for an interpretation in terms of surface tension changes accompanying the contraction of the film which is complete in less than a millisecond. The surface tension of sodium dodecyl sulphate solution decreases to below 15 mN/m (dyn/cm) under these conditions. As desorption is negligible, the data can be interpreted in terms of an extension of surface pressure-area per molecule curves towards high pressures and low areas. This extension shows an unexpected decrease of slope at low areas and indicates a rapid increase in intermolecular attractions as the surfactant ions become crowded on the surface.","PeriodicalId":341426,"journal":{"name":"Special Discussions of The Faraday Society","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134274518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Aqueous foam films stabilized by a non-ionic surface-active agent","authors":"J. S. Clunie, J. Corkill, J. Goodman, B. T. Ingram","doi":"10.1039/SD9700100030","DOIUrl":"https://doi.org/10.1039/SD9700100030","url":null,"abstract":"The thicknesses and tensions of black films formed by aqueous solutions of a pure, non-ionic surface-active agent, n-decyl methyl sulphoxide (DMS), have been measured at 298 and 308 K as a function of sodium chloride concentration. In the DMS + NaCl + H2O system, second black films are formed at low ionic strengths whereas first black films are formed at higher ionic strengths (> 100 mol m–3). Estimated values for the composite Hamaker constant for first and second black films have been obtained and compared with theoretical values.","PeriodicalId":341426,"journal":{"name":"Special Discussions of The Faraday Society","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125996235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Boundary layers of pure liquids at the Graphon surface","authors":"S. G. Ash, G. Findenegg","doi":"10.1039/SD9700100105","DOIUrl":"https://doi.org/10.1039/SD9700100105","url":null,"abstract":"Measurements of the volume changes which accompany the wetting of Graphon by n-alkanes, benzene and water, and the heats of wetting for the same systems, are analyzed. For the long-chain alkanes there is evidence for a pre-freezing phenomenon near the Graphon/liquid interface. For liquids composed of smaller molecules this effect is not found.","PeriodicalId":341426,"journal":{"name":"Special Discussions of The Faraday Society","volume":"9 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121009469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Response of an equilibrium film to external disturbances","authors":"A. Prins, M. Tempel","doi":"10.1039/SD9700100020","DOIUrl":"https://doi.org/10.1039/SD9700100020","url":null,"abstract":"An equilibrium film situated in air saturated with water vapour is subjected to a disturbance consisting of a rapid change of the temperature of the surrounding atmosphere. The resulting large change in film thickness is found to be due to exchange of water between film and atmosphere, and not to expansion or contraction of the film. Pseudo-equilibrium films of widely varying thickness can be formed by means of this process. For a film with a sufficiently large area, the thickness of an element far from the border is determined by the water vapour pressure equilibrium rather than by the disjoining pressure equilibrium. The thickness profile of a large, vertical film in a state of apparent rest is explained on the basis of the different time scales associated with the various equilibrium processes.","PeriodicalId":341426,"journal":{"name":"Special Discussions of The Faraday Society","volume":"95 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115691511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thickness of very thin films in elastohydrodynamic lubrication","authors":"A. Dyson","doi":"10.1039/SD9700100231","DOIUrl":"https://doi.org/10.1039/SD9700100231","url":null,"abstract":"Films of lubricant were formed between two loaded rolling steel discs, and the thicknesses of the films were estimated from measurements of the electrical capacitance between the discs. Two mineral oils and one synthetic diester were used as lubricants. The minimum film thicknesses ranged down to approximately 10 nm (100 A), and agreed approximately with the predictions of an isothermal Newtonian theory in which the viscosity of the lubricant, measured in bulk, was used. Of the four sets of results examined, only one, that for the di-ester, gave measured film thicknesses greater than the theoretical ones. The discrepancy of 13 % is probably within the systematic errors of the experiment and of the theory. With this exception, there was therefore no evidence that the viscosity of the lubricant was affected by the close proximity of the metal surfaces. The maximum shear rate in these experiments was of the order of 107 s–1, i.e., several orders of magnitude greater than those obtaining in other experiments reported in the literature, in which the viscosity of a fluid was increased by the presence of the surfaces.","PeriodicalId":341426,"journal":{"name":"Special Discussions of The Faraday Society","volume":"35 4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114622922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}