Synthesis of novel fluorous surfactants for microdroplet stabilisation in fluorous oil streams

The synthesis of a number of potential fluorous surfactants, prepared with a view to stabilising microdroplets in microfluidic systems is described. The surfactants comprised compounds with both perfluoropolyether (PFPE) and perfluoroalkyl (PFA) tails with three classes of hydrophilic head group, including crown ethers and hexaethylene glycol. Hydrophilic head groups and alkyl fluorous-based tails were coupled together via amide, ester and ether linkages to afford the fluorous surfactant candidates in good yields. The resulting molecules show promise in forming and stabilising both aqueous and nonaqueous microdroplets in fluorous oil streams within poly(dimethylsiloxane) (PDMS) devices to a greater degree than the pseudosurfactants commonly employed in microdroplet research. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.