Editors: | Kongoli F |
Publisher: | Flogen Star OUTREACH |
Publication Year: | 2014 |
Pages: | 578 pages |
ISBN: | 978-1-987820-07-2 |
ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
Core-shell microcapsules were generated using a polymer-induced liquid-precursor (PILP) mineralization process to deposit a calcium carbonate (CaCO3) mineral shell on the surface of surfactant-stabilized fluidic particles comprised of either oil-in-water emulsion droplets or liposomes. Morphological analyses were performed by various microscopic techniques, where it was observed that PILP droplets preferentially adsorb to anionic surfactants/lipids that stabilize the suspension, and due to their liquid-like character, coalesce to form a smooth and continuous mineral coating. The processing conditions for forming these CaCO3-coated microcapsules are benign, and they can virtually encapsulate any active agent of interest. Hydrophobic compounds, for example, can be dissolved in oil-in-water emulsions, while hydrophilic and/or hydrophobic compounds can be dissolved within liposomes, which can then be coated with the mineral shell. Confocal microscopy was used to demonstrate an oil-soluble fluorescent dye is encapsulated in the interior of the emulsion, or both hydrophilic and hydrophobic compounds are incorporated with the aqueous and hydrocarbon regions of liposomes, respectively. The metastable morphology of the CaCO3 shell enables a pH dependent degradation of the particles, allowing the release of the active agent of interest. These CaCO3-coated microcapsules can be dried down to a powder, while retaining the fluidic core, which could save in storage and transportation expenses because the large solution phase of the suspension is removed. We believe that these core-shell particles have a myriad of potential applications because of their inherent environmentally-benign composition and biocompatibility. Core-shell microcapsules, for example, could be used in environmental applications, such as release of pesticide or fertilizer, in chemical reactions, such as release of catalyst of specific reagents, in hair/skin care products for release of conditioner or other compounds, in health care for release of pharmaceutics, or in self-healing composites for release of a sealant capsule fracture.