.png){kind=icon}
Return
pH-Controlled Microbubble Shell Formation and Stabilization
.png){kind=icon}
PRE
AI
DOI：10.1021/la5007023.png)
.png){kind=icon}
Original request for help.png){kind=icon}
Share.png){kind=icon}
Save
Abstract
En 中文
We report on microbubbles with a shell self-assembled from an anionic perfluoroalkylated surfactant, perfluorooctyl(ethyl)phosphate (F8H2Phos). Microbubbles were formed and effectively stabilized from aqueous solutions of F8H2Phos at pH 5.6-8.5. This range overlaps the domains of existence of the monosodic and disodic salts. The shell morphology of microbubbles formed spontaneously by heating aqueous solutions of F8H2Phos was monitored during cooling, directly on the microscope's stage. At pH 5.6, the shell collapses through nucleation of folds, as typical for insoluble surfactants. At pH 8.5, no folds 10 were seen during shrinking. At higher pH, the microbubbles rapidly adsorb on the glass. The effect of pH (from 5.6 to 9.7) on adsorption kinetics of F8H2Phos at the air/water interface, and on the elasticity of its Gibbs films, was determined. At low pH, F8H2Phos is highly surface active. The interfacial film undergoes a dilute-to-condensed phase transition and a dramatic increase of elastic module, leading to extremely high values (up to 500 mN m(-1)). At high pH, the surfactant's adsorption is quasi-instantaneous, but interfacial tension lowering is limited, leading to very low elastic module (similar to 5 mN m(-1)). At pH 5.6 and 8.5, the interfacial tension of F8H2Phos adsorbed on millimetric bubbles and compressed at a rate similar to that exerted on micrometric bubbles during deflation is lower than the equilibrium interfacial tension. Langmuir monolayers of F8H2Phos are highly stable at low pH and feature a liquid expanded/liquid condensed transition; at high pH, they do not withstand compression. Both mono- and disodic F8H2Phos salts are needed to effectively stabilize microbubbles: the rapidly adsorbed disodic salt stabilizes a newly created air/water interface; the more surface active monosodic salt then replaces the more water-soluble disodic salt at the interface. During deflation, the surfactant shell undergoes a transition toward a highly elastic phase, which further contributes to bubble stabilization.
Keywords:
CONTRAST AGENTS
DRUG
SIZE
GENE
COLLAPSE
LIFETIME
BEHAVIOR
AI Summary
Key information extracted from the uploaded paper, including a brief overview, abstract, background, key highlights, visual analysis, and future outlook.
Journal
IF:
3.9
Papers:
5.4W
Citations:
10.6W
Organization
Cited Papers
ShareSaveShareSaveShareSaveShareSavePhospholipid-Coated Gas Bubble Engineering: Key Parameters for Size and Stability Control, as Determined by an Acoustical Method.png)
LANGMUIR
LANGMUIRIF3.9
PREAI
ShareSaveInfluence of lipid shell physicochemical properties on ultrasound-induced microbubble destruction
OAAI
OAAIShareSaveDissolution behavior of lipid monolayer-coated, air-filled microbubbles: Effect of lipid hydrophobic chain lengthLANGMUIR
LANGMUIRIF3.9
PREAI
ShareSave
View more