Polymer microcapsules with "foamed" membranes.
This article describes the preparation of capsules displaying craters at their surfaces and independent holes inside their membranes. These poly(methylmethacrylate) capsules of 20 to 200 microm diameter are prepared by a solvent evaporation process and typically contain a dispersant, polyvinyl alcohol, and an excipient, namely, a fatty acid triglyceride (miglyol 812). Spectroscopic methods showed that, depending on the miglyol content, the craters at the surface exhibited sizes of about 1 to 2 microm, whereas the core structure of the membrane changed significantly, typically from "soft-part-of-bread" up to "foamed"-like aspects. Among several spectroscopy techniques, confocal fluorescence microscopy confirmed that the capsules retained the miglyol in their core and not in the craters or holes, even after centrifugation and handling. This technique also showed that holes in the membrane are filled with water. A possible analysis of the "foaming" phenomenon based on the surface tensions of different oils, as well as their optimal hydrophile-lipophile balance (HLBO), is added to generalize the concept.
Lavergne
Fleur-Marie
FM
Institut Charles Gerhardt, UMR5253 CNRS/UM2/ENSCM/UM1, 8 Rue de l'Ecole Normale, 34296 Montpellier Cedex 5, France.
Cot
Didier
D
Ganachaud
François
F
D002214:Capsules / Q000737:chemistry; D008081:Liposomes / Q000737:chemistry*; D010316:Particle Size; D011142:Polyvinyl Alcohol / Q000737:chemistry*; D014280:Triglycerides / Q000737:chemistry*
D002214:Capsules; D008081:Liposomes; D014280:Triglycerides; C022834:miglyol 812; D011142:Polyvinyl Alcohol