title: Effects of surfactant and electrolyte concentrations on bubble formation and stabilization.
abstract: As interest in the application of microbubbles grows, it is becoming increasingly important to understand the factors affecting their formation and properties in order to effectively generate microbubbles. This paper investigates the effect of surfactant concentration and electrolyte addition on the size distribution and stability of microbubbles. The anionic surfactant sodium dodecyl sulfate (SDS) was used as the surfactant. Minimum bubble diameter and maximum stability were achieved at surfactant concentrations above the CMC. The effect of the electrolyte addition was studied by adding sodium chloride (NaCl) at an SDS concentration below the critical micelle concentration (CMC). Addition of NaCl decreased bubble size and improved bubble preparation to a certain extent. The addition of salt at low concentrations did not affect the surface tension; however, the surface tension was reduced as salt concentration was increased and reached a constant value for NaCl concentrations above 0.25%. The presence of NaCl resulted in a significant decrease in zeta-potential, implying a reduction in the surface charge of SDS micelles. This result suggests that the presence of NaCl may improve the generation and stability of bubbles by enhancing the structures of the adsorption monolayer and interfacial film.
authors.affiliation: Food Engineering Division, National Food Research Institute, 2-1-12 Kannondai, Tsukuba, Ibaraki 305-8642, Japan. xuqingyi@affrc.go.jp
authors.forename: Qingyi
authors.initials: Q
authors.lastname: Xu
authors.forename: Mitsutoshi
authors.initials: M
authors.lastname: Nakajima
authors.forename: Sosaku
authors.initials: S
authors.lastname: Ichikawa
authors.forename: Nobutaka
authors.initials: N
authors.lastname: Nakamura
authors.forename: Poritosh
authors.initials: P
authors.lastname: Roy
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Okadome
authors.forename: Takeo
authors.initials: T
authors.lastname: Shiina
mesh_terms: D004573:Electrolytes / Q000737:chemistry*; D008823:Micelles; D008956:Models, Chemical; D012965:Sodium Chloride / Q000737:chemistry*; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry*; D013500:Surface Tension; D013501:Surface-Active Agents / Q000737:chemistry*
chemical_list: D004573:Electrolytes; D008823:Micelles; D013501:Surface-Active Agents; D012967:Sodium Dodecyl Sulfate; D012965:Sodium Chloride