T. Kawakatsu et al., RELATIONSHIP BETWEEN CONCENTRATION OF SUR FACTANT AND PRESSURE FOR DROPLET CREATION, AND EFFECT ON DROPLET SIZE IN MICROCHANNEL O W EMULSIFICATION/, Kagaku kogaku ronbunshu, 24(2), 1998, pp. 313-317
O/W emulsion was produced with use of microchannels constructed on a s
ingle-crystal silicon substrate plate by micromachining technology. Th
e relationship between concentration of surfactant and pressure for dr
oplet generation is studied, and the effect of them on droplet size is
also investigated. Triolein and sodium lauryl sulfate (SDS) aqueous s
olution were used for oil and water phases, respectively. As SDS conce
ntration increases, the interfacial tension between oil and water phas
es decreases and pressure for droplet generation becomes low, When the
SDS concentration exceeds the critical micelle concentration, the int
erfacial tension and the pressure for droplet generation are constant.
A similar phenomena is observed for the SDS solution to which NaCl is
added. Average droplet size was 20 mu m and independent of the SDS co
ncentration and pressure. The geometric standard deviation is below 1.
03, which indicates monodispersion of droplets.