title: Stability of an encapsulated bubble shell.
abstract: The stability of an encapsulated bubble filled with gas is studied where gas is allowed to diffuse out of the bubble. A mechanistic model that takes into account shell stiffness and surface tension is considered. A critical shell radius for loss of mechanical stability is derived based on a technique adapted for small radius, where surface tension effects become substantial. A new parameter is defined that determines the relative importance of surface tension forces and shell stiffness for shell stability. The developed technique allows to predict, for a given bubble population and gas saturation level of the surrounding liquid, a range of bubble sizes which may collapse in time. Surface tension effects are dominant in determining the critical radius but have a negligible effect on the minimal radius for collapse. The influence of the surface tension on the stability of the shell is illustrated for Optison, a typical ultrasound contrast agent.
authors.affiliation: The Department of Biomedical Engineering, Technion, Haifa 32000, Israel. agboris@tx.technion.ac.il
authors.forename: Boris
authors.initials: B
authors.lastname: Krasovitski
authors.forename: Eitan
authors.initials: E
authors.lastname: Kimmel
mesh_terms: D003198:Computer Simulation; D003287:Contrast Media / Q000737:chemistry*; D004058:Diffusion; D004548:Elasticity; D005740:Gases / Q000737:chemistry; D006801:Humans; D045423:Microbubbles; D008956:Models, Chemical; D011312:Pressure; D013499:Surface Properties; D013500:Surface Tension; D014463:Ultrasonography
chemical_list: D003287:Contrast Media; D005740:Gases