Topic
Surface tension
About: Surface tension is a research topic. Over the lifetime, 25410 publications have been published within this topic receiving 695471 citations.
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TL;DR: A benchmark for force fields is devised in order to test the ability of existing force fields to reproduce some key properties of organic liquids, namely, the density, enthalpy of vaporization, the surface tension, the heat capacity at constant volume and pressure, the isothermal compressibility, the volumetric expansion coefficient, and the static dielectric constant.
Abstract: The chemical composition of small organic molecules is often very similar to amino acid side chains or the bases in nucleic acids, and hence there is no a priori reason why a molecular mechanics force field could not describe both organic liquids and biomolecules with a single parameter set. Here, we devise a benchmark for force fields in order to test the ability of existing force fields to reproduce some key properties of organic liquids, namely, the density, enthalpy of vaporization, the surface tension, the heat capacity at constant volume and pressure, the isothermal compressibility, the volumetric expansion coefficient, and the static dielectric constant. Well over 1200 experimental measurements were used for comparison to the simulations of 146 organic liquids. Novel polynomial interpolations of the dielectric constant (32 molecules), heat capacity at constant pressure (three molecules), and the isothermal compressibility (53 molecules) as a function of the temperature have been made, based on expe...
602 citations
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TL;DR: A general introduction to foams, the initial stages in the production of foams in aqueous solution, foam structures and the classification of bulk foams according to their lifetimes and stability are presented in this paper.
601 citations
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11 Mar 2005
TL;DR: In this paper, the authors present a general classification of surface active agents and their properties, including the role of Surfactants in the formation and stabilization of solid/liquid interfaces.
Abstract: Preface.1 Introduction.1.1 General Classification of Surface Active Agents.1.2 Anionic Surfactants.1.3 Cationic Surfactants.1.4 Amphoteric (Zwitterionic) Surfactants.1.5 Nonionic Surfactants.1.6 Speciality Surfactants - Fluorocarbon and Silicone Surfactants.1.7 Polymeric Surfactants.1.8 Toxicological and Environmental Aspects of Surfactants.2 Physical Chemistry of Surfactant Solutions.2.1 Properties of Solutions of Surface Active Agents.2.2 Solubility-Temperature Relationship for Surfactants.2.3 Thermodynamics of Micellization.2.4 Micellization in Surfactant Mixtures (Mixed Micelles).2.5 Surfactant-Polymer Interaction.3 Phase Behavior of Surfactant Systems.3.1 Solubility-Temperature Relationship for Ionic Surfactants.3.2 Surfactant Self-Assembly.3.3 Structure of Liquid Crystalline Phases.3.4 Experimental Studies of the Phase Behaviour of Surfactants.3.5 Phase Diagrams of Ionic Surfactants.3.6 Phase Diagrams of Nonionic Surfactants.4 Adsorption of Surfactants at the Air/Liquid and Liquid/Liquid Interfaces.4.1 Introduction.4.2 Adsorption of Surfactants.4.3 Interfacial Tension Measurements.5 Adsorption of Surfactants and Polymeric Surfactants at the Solid/Liquid Interface.5.1 Introduction.5.2 Surfactant Adsorption.5.3 Adsorption of Polymeric Surfactants at the Solid/Liquid Interface.5.4 Adsorption and Conformation of Polymeric Surfactants at Interfaces.5.5 Experimental Methods for Measurement of Adsorption Parameters for Polymeric Surfactants.6 Applications of Surfactants in Emulsion Formation and Stabilisation.6.1 Introduction.6.2 Physical Chemistry of Emulsion Systems.6.3 Mechanism of Emulsification.6.4 Methods of Emulsification.6.5 Role of Surfactants in Emulsion Formation.6.6 Selection of Emulsifiers.6.7 Cohesive Energy Ratio (CER) Concept for Emulsifier Selection.6.8 Critical Packing Parameter (CPP) for Emulsifier Selection.6.9 Creaming or Sedimentation of Emulsions.6.10 Flocculation of Emulsions.6.11 Ostwald Ripening.6.12 Emulsion Coalescence.6.13 Phase Inversion.6.14 Rheology of Emulsions.6.15 Interfacial Rheology.6.16 Investigations of Bulk Rheology of Emulsion Systems.6.17 Experimental Methods for Assessing Emulsion Stability.7 Surfactants as Dispersants and Stabilisation of Suspensions.7.1 Introduction.7.2 Role of Surfactants in Preparation of Solid/Liquid Dispersions.7.3 Effect of Surfactant Adsorption.7.4 Wetting of Powders by Liquids.7.5 Rate of Penetration of Liquids.7.6 Structure of the Solid/Liquid Interface.7.7 Structure of the Electrical Double Layer.7.8 Electrical Double Layer Repulsion.7.9 Van der Waals Attraction.7.10 Total Energy of Interaction: Deryaguin-Landau-Verwey-Overbeek (DLVO) Theory.7.11 Criteria for Stabilisation of Dispersions with Double Layer Interaction.7.12 Electrokinetic Phenomena and the Zeta Potential.7.13 Calculation of Zeta Potential.7.14 Measurement of Electrophoretic Mobility.7.15 General Classification of Dispersing Agents.7.16 Steric Stabilisation of Suspensions.7.17 Interaction Between Particles Containing Adsorbed Polymer Layers.7.18 Criteria for Effective Steric Stabilisation.7.19 Flocculation of Sterically Stabilised Dispersions.7.20 Properties of Concentrated Suspensions.7.21 Characterisation of Suspensions and Assessment of their Stability.7.22 Bulk Properties of Suspensions.7.23 Sedimentation of Suspensions and Prevention of Formation of Dilatant Sediments (Clays).7.24 Prevention of Sedimentation and Formation of Dilatant Sediments.8 Surfactants in Foams.8.1 Introduction.8.2 Foam Preparation.8.3 Foam Structure.8.4 Classification of Foam Stability.8.5 Drainage and Thinning of Foam Films.8.6 Theories of Foam Stability.8.7 Foam Inhibitors.8.8 Physical Properties of Foams.8.9 Experimental Techniques for Studying Foams.9 Surfactants in Nano-Emulsions.9.1 Introduction.9.2 Mechanism of Emulsification.9.3 Methods of Emulsification and the Role of Surfactants.9.4 Preparation of Nano-Emulsions.9.5 Steric Stabilization and the Role of the Adsorbed Layer Thickness.9.6 Ostwald Ripening.9.7 Practical Examples of Nano-Emulsions.10 Microemulsions.10.1 Introduction.10.2 Thermodynamic Definition of Microemulsions.10.3 Mixed Film and Solubilisation Theories of Microemulsions.10.4 Thermodynamic Theory of Microemulsion Formation.10.5 Free Energy of Formation of Microemulsion.10.6 Factors Determining W/O versus O/W Microemulsions.10.7 Characterisation of Microemulsions Using Scattering Techniques.11 Role of Surfactants in Wetting, Spreading and Adhesion.11.1 General Introduction.11.2 Concept of Contact Angle.11.3 Adhesion Tension.11.4 Work of Adhesion Wa.11.5 Work of Cohesion.11.6 Calculation of Surface Tension and Contact Angle.11.7 Spreading of Liquids on Surfaces.11.8 Contact Angle Hysteresis.11.9 Critical Surface Tension of Wetting and the Role of Surfactants.11.10 Effect of Surfactant Adsorption.11.11 Measurement of Contact Angles.11.12 Dynamic Processes of Adsorption and Wetting.11.13 Wetting Kinetics.11.14 Adhesion.11.15 Deposition of Particles on Surfaces.11.16 Particle-Surface Adhesion.11.17 Role of Particle Deposition and Adhesion in Detergency.12 Surfactants in Personal Care and Cosmetics.12.1 Introduction.12.2 Surfactants Used in Cosmetic Formulations.12.3 Cosmetic Emulsions.12.4 Nano-Emulsions in Cosmetics.12.5 Microemulsions in Cosmetics.12.6 Liposomes (Vesicles).12.7 Multiple Emulsions.12.8 Polymeric Surfactants and Polymers in Personal Care and Cosmetic Formulations.12.9 Industrial Examples of Personal Care Formulations and the Role of Surfactants.13 Surfactants in Pharmaceutical Formulations.13.1 General Introduction.13.2 Surfactants in Disperse Systems.13.3 Electrostatic Stabilisation of Disperse Systems.13.4 Steric Stabilization of Disperse Systems.13.5 Surface Activity and Colloidal Properties of Drugs.13.6 Biological Implications of the Presence of Surfactants in Pharmaceutical Formulations.13.7 Aspects of Surfactant Toxicity.13.8 Solubilised Systems.13.9 Pharmaceutical Suspensions.13.10 Pharmaceutical Emulsions.13.11 Multiple Emulsions in Pharmacy.13.12 Liposomes and Vesicles in Pharmacy.13.13 Nano-particles, Drug Delivery and Drug Targeting.13.14 Topical Formulations and Semi-solid Systems.14 Applications of Surfactants in Agrochemicals.14.1 Introduction.14.2 Emulsifiable Concentrates.14.3 Concentrated Emulsions in Agrochemicals (EWs).14.4 Suspension Concentrates (SCs).14.5 Microemulsions in Agrochemicals.14.6 Role of Surfactants in Biological Enhancement.15 Surfactants in the Food Industry.15.1 Introduction.15.2 Interaction Between Food-grade Surfactants and Water.15.3 Proteins as Emulsifiers.15.4 Protein-Polysaccharide Interactions in Food Colloids.15.5 Polysaccharide-Surfactant Interactions.15.6 Surfactant Association Structures, Microemulsions and Emulsions in Food.15.7 Effect of Food Surfactants on the Rheology of Food Emulsions.15.8 Practical Applications of Food Colloids.Subject Index.
598 citations
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TL;DR: In this article, an atomic force microscope with an optical lever detection system was used to measure the absolute force applied by a tip on a surface, which can be as low as 10−9 N or less in water and 10−7 N in air.
Abstract: A new atomic force microscope, which combines a microfabricated cantilever with an optical lever detection system, now makes it possible to measure the absolute force applied by a tip on a surface. This absolute force has been measured as a function of distance (=position of the surface) in air and water over a range of 600 nm. In the absolute force versus distance curves there are two transitions from touching the surface to a total release in air caused by van der Waals interaction and surface tension. One transition is due to lifting off the surface; the other is due to lifting out of an adsorbed layer on the surface. In water there is just one transition due to lifting off the surface. There is also a transition in air and water when the totally released tip is pulled down to touch the surface as the surface and tip are brought together. Based on the force versus distance curves, we propose a procedure to set the lowest possible imaging force. It can now be as low as 10−9 N or less in water and 10−7 N...
598 citations
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TL;DR: It has been found that surfaces representing acidic and alkaline conditions have a significant influence on both the shape of the nanocrystals and the anatase-to-rutile transition size.
Abstract: The effects of surface chemistry on the morphology and phase stability of titanium dioxide nanoparticles have been investigated using a thermodynamic model based on surface free energies and surface tensions obtained from first principles calculations. It has been found that surfaces representing acidic and alkaline conditions have a significant influence on both the shape of the nanocrystals and the anatase-to-rutile transition size. The latter introduces the possibility of inducing phase transitions by changing the surface chemistry.
595 citations