Fluorosurfactants for microdroplets: interfacial tension analysis.
Quantitative analysis of a number of potential fluorous surfactants, prepared with a view to stabilisation of microdroplets in microfluidic systems is presented. The surfactants tested comprised compounds with both perfluoropolyether (PFPE) and perfluoroalkyl (PFA) tails, along with three classes of hydrophilic head group, including crown ethers and hexaethylene gylcol. Surfactants were tested for activity using the pendant drop technique. Six compounds proved highly effective and efficient surfactants, with gamma(CMC)<10 mN/m and CMCs in the sub-millimolar range. These six compounds stabilised aqueous microdroplets in fluorous oils within poly(dimethylsiloxane) (PDMS) microdevices to a greater degree than commonly used pseudosurfactants such as perfluorooctanol.
Holt
Daniel J
DJ
University Chemical Laboratory, Lensfield Road, Cambridge CB2 1EW, United Kingdom.
Payne
Richard J
RJ
Chow
Wing Ying
WY
Abell
Chris
C