Dresden 2009 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 39: POSTERS Colloids and Liquids
CPP 39.25: Poster
Donnerstag, 26. März 2009, 17:00–19:30, P3
Step-Emulsification Microfluidics for the Generation of Spherical Mesoporous Silica Particles — •Venkatachalam Chokkalingam1, Boris Weidenhof2, WIlhelm Maier2, Stephan Herminghaus1, and Ralf Seemann1, 3 — 1Max Planck Institute for Dynamics and Self-Organization, Goettingen 37073, Germany — 2Technical Chemistry, Saarland University, Saarbruecken 66123, Germany. — 3Experimental Physics, Saarland University, Saarbrücken 66123, Germany
We explore two phase microfluidics for complex chemical reactions. By dispersing different reagents into droplets and subsequently merging the droplets containing the different reagents, we realize chemical reactions, which are neither possible in single phase microfluidics, nor in droplet based microfluidics if the reagents are already mixed before being dispersed into droplets. We explore this explicitly for the production of porous silica particles from sol-gel chemistry. Regular pairs of aqueous droplets containing tetramethoxysilane (TMOS) and ammonia, respectively, are formed. The sol-gel reaction is started by merging the individual droplets using either electrocoalescence or a geometrical constriction. The concentration of the solutions is adjusted such, that the gel is fully developed when the coalesced droplets are collected outside of the microfluidic device for subsequent drying and heat treatment. The resulting silica particles have a diameter of a few micrometers, only. Further BET surface area analysis yields the chemical properties of the silica particles obtained. Particles obtained have a pore radius of about 4.5 nm and a surface area of about 600 sq.m/g.