Thermodynamic Stability Analysis of Microbubbles Confined in a Liquid Droplet.

A thermodynamic stability analysis of microbubbles in an enclosed volume of a volatile liquid-noncondensable gas solution was performed. The stability conditions for the formation of the bubbles and the relationship between the equilibrium bubble radius and the equilibrium bubble number were investigated. The calculation results show that even if the saturation vapor pressure of a volatile liquid is higher than the pressure of the liquid phase, stable noncondensable gas bubbles appear in a closed system.

Factors affecting the size and uniformity of hollow poly(lactic acid) microcapsules fabricated from microbubble templates.

Hollow microcapsules of poly(lactic acid) (PLA) were fabricated using the bubble template method, which involves the nucleation of bubbles inside droplets of a dichloromethane solution of PLA prepared in a continuum medium of an aqueous solution of poly(vinyl alcohol) (PVA). PLA-covered microbubbles are formed by PLA adsorbing onto the microbubble surface and then spontaneously released from the dichloromethane droplets into the surrounding aqueous solution. Thereby, hollow PLA microcapsules are formed.

Fabrication of hollow poly(lactic acid) microcapsules from microbubble templates.

Hollow microcapsules are expected to be integral components of drug delivery systems in medical and pharmaceutical applications. Among the methods studied, the bubble template method (Makuta et al. Mater.

Fabrication of hollow melamine-formaldehyde microcapsules from microbubble templates.

A fabrication method for hollow melamine-formaldehyde microcapsules from microbubble templates is presented. This method is based on the direct encapsulation of microbubbles, and thus does not require a liquid- or solid-core decomposition process. This study determined the conditions for controlling the surface morphology, shell thickness, and diameter distribution of hollow microcapsules.