Spontaneous self-assembly and structure of perfluoroalkylalkane surfactant hemimicelles by molecular dynamics simulations

Significance Semifluorinated alkanes surfactants spontaneously form nanostructured Langmuir films at the surface of water, consisting of highly organized arrays of hemimicelles. These supramolecular nanostructures are potential candidates for numerous applications, from smart materials to medical devices. Despite all efforts, the principles governing the formation and structure of these hemimicelles are not understood. Atomistic molecular-dynamics (MD) simulations show the spontaneous formation of such aggregates strikingly resembling those experimentally observed, supporting a rational explanation for the formation, size and shape of the hemimicelles. The simulated grazing incidence X-ray diffraction spectrum matches that obtained experimentally, fully validating the MD results. Given the simplicity of these “primitive” amphiphiles compared with the common hydrophilic/hydrophobic surfactants, these results can contribute to understand self-assembly processes in general.