Tubular microstructures made from nonchiral single-chain fluorinated amphiphiles: impact of the structure of the hydrophobic chain on the rolling-up of bilayer membrane.

The nonchiral, single-chain fluorinated amphiphiles derived from dimorpholinophosphate, C(n)F(2n+1)(CH(2))(m)OP(O)N(CH(2)CH(2))(2)O (FnCmDMPs), form hollow tubular bilayer-based self-assemblies when dispersed in water, ethanol/water mixtures, and dimethylformamide. The fluorinated tubules are highly stable and sturdy. Upon heating, they transform reversibly into giant multilamellar vesicles. Uncommon U-shaped and V-shaped coiled membranes were obtained from mixtures of FnCmDMPs. Depending on conditions, fluorinated tubules can evolve with time into collapsed flattened crystallized needles. The successive steps involved in the formation and evolution of these tubules were identified, and the specific features of fluorinated chains that are relevant to membrane coiling and tubule formation are discussed.