Cell membrane as a model for the design of semifluorinated ion-selective nanostructured supramolecular systems

The synthesis and polymerization of two AB3 tapered, self-assembling methacrylate monomers ( and ) based on a first generation semifluorinated alkyl-substituted monodendron (i.e. minidendron) are described. These monomers contain either a benzo-15-crown-5 derivative, which is incorporated via the esterification of 4′-hydroxymethyl-1,4,7,10,13-pentaoxabenzocyclopentadecane or a podant group, which is incorporated via the monoesterification of tetraethylene glycol at its focal point, and both bear polymerizable groups on their periphery. The corresponding polymers () self-assemble and subsequently self-organize into supramolecular networks, which form a 2-D hexagonal columnar lattice via the fluorophobic effect. These networks consist of a continuous phase, which is based on the semifluorinated, paraffinic barrier layer and which is perforated in a hexagonal array by ion-selective or ion-active channels constructed from the benzo crown-ether and tetraethylene glycol respectively. The replacement of alkyl groups from the periphery of the tapered monodendrons with semifluorinated ones induces the self-assembly and, subsequently, the self-organization into supramolecular networks. These networks form 2-D hexagonal columnar lattices with thermal stability in some cases of up to 110°C. The design of such functional supramolecular systems was inspired by the bilayer fluid mosaic structure of the cell membrane. The lipid bilayer of the cell membrane, which in its ordered state acts as a barrier to the passage of polar molecules, was replaced with the semifluorinated paraffinic barrier, while the protein-based ionic channels were replaced with benzo-15-crown-5 and tetraethylene glycol based channels. The resulting supramolecular material has the mechanical integrity required for both ion-active and ion-selective nanostructured supramolecular systems.