The Science of Defoaming Theory, Experiment and Applications

In the 20 years since the publication of the author’s multi-contributor volume on defoaming, a vast amount of new work has been published and many new insights have been revealed. A cohesive, single-authored book, The Science of Defoaming: Theory, Experiment and Applications provides comprehensive coverage of the topic. It describes the mode of action of antifoams, presenting the relevant theory and the supporting experimental evidence. Beginning with an introductory chapter that discusses the intrinsic properties of foam, the book then describes experimental methods for measuring foam properties important for studying antifoam action and techniques used in establishing the mode of action of antifoams.Since most commercially effective antifoams are oil based, a chapter is devoted to the entry and spreading behavior of oils and the role of thin film forces in determining that behavior. The book reviews the mode of action of antifoams, including theories of antifoam mechanisms and the role of bridging foam films by particles and oil drops. It also addresses issues related to the effect of antifoam concentration on foam formation by air entrainment and the process of deactivation of mixed oil–particle antifoams during dispersal and foam generation.For applications where chemical antifoam use is unacceptable, the text examines mechanical means of defoaming, such as the use of rotary devices and ultrasound. The final chapters consider the application of defoaming in radically different contexts including waterborne latex paints and varnishes, machine washing of textiles, gas–oil separation in crude oil production, and cardiopulmonary bypass surgery. Focusing on the basic science of defoaming, this book presents a balanced view, which also addresses the challenges that may arise for these specific defoaming applications.

Some General Properties of FoamsIntroductionThe Structure of FoamsFoam FilmsProcesses Accompanying Aging of FoamSummarizing RemarksExperimental Methods for Study of Foam and Antifoam ActionIntroductionMeasurement of FoamObservations With Single Foam FilmsAir–Water–Oil Pseudoemulsion FilmsSpreading Behavior of OilsSummarizing RemarksReferencesOils at Interfaces: Entry Coefficients, Spreading Coefficients, and Thin Film forcesIntroduction Classical Entry and Spreading CoefficientsGeneralized Entry Coefficients, Pseudoemulsion Films, and Thin Film forcesMode of Rupture of Pseudoemulsion FilmsGeneralized Spreading Coefficients and Thin Film forcesSpreading Behavior of Typical Antifoam Oils at Aqueous SurfacesNon-Equilibrium Effects due to Surfactant TransportSummarizing RemarksReferencesMode of Action of AntifoamsIntroductionAntifoam Effects due to Solubilized OilsEffect on Foamability of Mesophase Precipitation in Aqueous Surfactant SolutionsSurface Tension Gradients and Theories of Antifoam MechanismOil Bridges and Antifoam MechanismAntifoam Behavior of Emulsified LiquidsInert Hydrophobic Particles and Capillary Theories of Antifoam Mechanism for Aqueous SystemsMixtures of Hydrophobic Particles and Oils as Antifoams for Aqueous SystemsSummarizing RemarksReferencesAppendix 4.1: Some Examples of Early Antifoam Patents Concerning Mixtures of Hydrophobic Particles and OilsEffect of Antifoam Concentration on Volumes of Foam Generated by Air EntrainmentPhenomenologyStatistical Theory of Antifoam ActionSummarizing RemarksAppendix 5.1: Effect of Excluded Volume on Antifoam Concentration in A Film Exhibiting Reynolds DrainageReferencesDeactivation of Mixed Oil–Particle Antifoams During Dispersal and Foam Generation in Aqueous MediaIntroduction Deactivation of Antifoam Effect of Polydimethylsiloxane Oils Without ParticlesEarly Work With Hydrophobed Silica–Polydimethylsiloxane AntifoamsDeactivation of Hydrophobed Silica–Polydimethylsiloxane Antifoams By DisproportionationEffect of Oil Viscosity on Deactivation of Hydrophobed Silica–Polydimethylsiloxane AntifoamsDeactivation in Other Types of Oil–Particle AntifoamsTheories of Foam Volume Growth in Presence of Deactivating AntifoamSummarizing RemarksReferencesMechanical Methods for DefoamingIntroductionDefoaming Using Rotary DevicesDefoaming Using UltrasoundDefoaming Using Packed Beds of Appropriate WettabilitySummarizing RemarksReferencesAppendix 7.1: Summary of Empirical Studies of Mechanical Defoaming by Rotary DevicesAntifoams for Detergent ProductsIntroductionPowders for Machine Washing of LaundryLiquids for Machine Washing of LaundryMachine DishwashingGeneral Hard-Surface Cleaning ProductsSummarizing RemarksAppendix 8.1: Examples of Patents Claiming Incorporation of Polysiloxane-Hydrophobed Silica Antifoams in Detergent Powders for Machine Washing of TextilesReferencesControl of Foam in Waterborne Latex Paints and VarnishesIntroductionFoam and Antifoam BehaviourSpecific Issues Concerning Oil-Based AntifoamsSummarizing RemarksReferencesAntifoams for Gas–Oil Separation in Crude Oil ProductionIntroductionSurface Activity at Gas–Hydrocarbon and Gas–Crude Oil interfacesCauses of Foam formation in Gas–Crude Oil SystemsUse of AntifoamsSummarizing RemarksReferencesMedical Applications of DefoamingIntroductionUse of Simethicone Antifoam in Treatment of Gastrointestinal GasDefoaming of Blood During Cardiopulmonary Bypass SurgerySummarizing RemarksReferences

After working for Unilever Research for almost thirty years at Port Sunlight and for a short time at Bangalore, Peter Garrett retired, acquiring visiting professorships at the University of Manchester in the United Kingdom and briefly at Rice University, Houston, Texas. He has worked on various aspects of interfacial science in a career lasting 40 years. These included the equilibrium and dynamic adsorption behavior of surfactant solutions, solubilization in microemulsions, kinetics of surfactant dissolution and mesophase growth, and of course both the basic science of defoaming and its application especially in the detergents industry.Professor Garrett is author or coauthor of more than 30 journal articles and is named as inventor on 14 patents, the majority of which concerned the application of antifoam technology. He is also editor of the book Defoaming, Theory and Applications published in 1993. A member of the Royal Society of Chemistry, he received his Ph.D. from the University of Leicester in the United Kingdom in 1971.