Fabrication of Hollow Polylactic Acid Microcapsules From Microbubble Templates

Hollow polylactic acid (PLA) microcapsules from microbubbles templates are being generated inside methylene chloride (CH₂Cl₂) droplets formed in a poly-vinyl alcohol aqueous solution (PVA_aq). By stably keeping the microbubbles, PLA can absorb to the bubble surface and become the shell of the microcapsules. It is desired to accurately control the final microcapsule radius size. Thus, in the following document, details on a series of experiments that aim to control the microcapsule final radius are covered. In situ, microscope imaging (ECLIPSE Ti-E, Nikon Corporation, Tokyo, Japan) was used to analyze the final radius size. PLA was also stained with Nile Red (excites at 485 nm, emits at 525 nm) for fluorescence visualization. These procedures allowed the verification of the parameters that influences the final microcapsule size. Experiments were performed at room temperature. Herein, details on the experimental arrangement, results and justification for how each parameter affects the final microcapsule radius.