Mixing characterization inside microdroplets engineered on a microcoalescer

Flavie Sarrazin (1) , Laurent Prat (1) , Nathalie Di Miceli Raimondi (1) , Galder Cristobal (2) , D.R. Link (3) , D.A. Weitz (3)

1 LGC - Laboratoire de Génie Chimique
2 LOF - Laboratoire du Futur
3 Department of Physics [Harvard University]

We use a microdevice where microdroplets of reagents are generated and coalesce in a carrier continuous phase. The work focuses on the characterization of the mixing step inside the droplets, in the perspective to use them for chemical kinetic data acquisition. A dye and water are used, and an acid–base instantaneous chemical reaction is monitored thanks to a colored indicator. Acquisitions are done with a high-speed camera coupled to a microscope and a mixing parameter is calculated by image analysis. Different angles of bended channels and different ways of coalescence are compared. It is shown that the homogenization of the droplets can be reached in less than 10 ms after coalescence. This is achieved by forcing the droplets to coalesce in a “shifted” way, and later by adding 45◦ angle bends along the channel.

Mots clés: Microreactor; Micro droplet; Mixing study; Fast reaction

Domaines: Génie chimique

Flavie Sarrazin, Laurent Prat, Nathalie Di Miceli Raimondi, Galder Cristobal, D.R. Link, et al.. Mixing characterization inside microdroplets engineered on a microcoalescer. Chemical Engineering Science, 2007, 6 (4), pp.1042-1048. ⟨10.1016/j.ces.2006.10.013⟩. ⟨hal-03594268⟩