| Micron-scale bubbles (microbubbles) are of considerable interest in environmental, biomedical, and food sciences. The low cost food emulsifiers, which are used to stabilize the gas core of the microbubble, consist of a mixture of monoglycerides, diglycerides and sodium steroyl lactylate in combination with polyethylene glycol (PEG) 40 sterate. Langmuir trough methods and fluorescence microscopy were combined to investigate the surface tension, interfacial elastic modulus, phase behavior and microstructure of monolayer shells coating these microbubbles.;Polydisperse coated microbubbles can be generated using a probe sonication technique. The dissolution behavior of a microbubble in different unsaturated media was studied using a fluorescence microscope. These dissolution behaviors, involving the buckling and rupture of the coated monolayer, can be explained by the phase behavior of emulsifiers and their roles in the stabilization of microbubbles in aqueous systems.;Nearly monodispersed populations of microbubbles ranged in 120--200mum were produced using flow focusing Technique. Sufficient short-term stability in size allows the rheological properties of microbubble suspension to be obtained by rheometer. The effect of shearing on the bubble sizes is investigated. There results show that the microbubble suspensions are viscoelastic and exhibit power law behavior. The relationship between the air fraction of the suspension and fluid rheology is determined. |
