Jeremy Steinbacher - Rapid Self-Assembly of Core−Shell Organosilicon Microcapsules within a Microfluidic Device

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      Publication Details (including relevant citation   information): Steinbacher, Jeremy L., Moy, Rebecca W.   Y., Price, Kristin E., Cummings, Meredith A., Roychowdhury,   Chandrani, Buffy, Jarrod J., Olbricht, William L., Haaf, Michael,   McQuade, D. Tyler, J. Am. Chem. Soc.,   2006, 128 (29), pp 9442-9447

      Abstract: The preparation of hierarchically   structured organosilicon microcapsules from commercially   available starting materials is described. Using a microfluidic   device, an emulsion of dichlorodiphenylsilane is formed in a   continuous phase of aqueous glycerol. The silane droplets undergo   hydrolysis, condensation, and crystallization within minutes to   form self-assembled, core?shell microcapsules. The microparticles   have been characterized with light and electron microscopy,   nuclear magnetic resonance spectroscopy (NMR), diffusion-ordered   NMR spectroscopy (DOSY), Fourier transform infrared spectroscopy   (FTIR), differential scanning calorimetry (DSC), and powder X-ray   diffraction (XRD). The characterization data show that the   microcapsule walls consist of amorphous, oligomeric   poly(diphenylsiloxane) surrounded by a spiny layer of crystalline   diphenylsilanediol. Glycerol is occluded within the wall material   but is not covalently bound to the silicon components. Glycerol   is a crucial element for producing low-dispersity microcapsules   with well-ordered surface spines, as the use of methyl cellulose   as viscomodifier yields amorphous surfaces.

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