188438-95-1Relevant academic research and scientific papers
Cell membrane as a model for the design of semifluorinated ion-selective nanostructured supramolecular systems
Percec, Virgil,Bera, Tushar K
, p. 4031 - 4040 (2002)
The synthesis and polymerization of two AB3 tapered, self-assembling methacrylate monomers (12 and 13) 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 (14-16) 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.
Self-organizable vesicular columns assembled from polymers dendronized with semifluorinated janus dendrimers act as reverse thermal actuators
Percec, Virgil,Imam, Mohammad R.,Peterca, Mihai,Leowanawat, Pawaret
, p. 4408 - 4420 (2012/04/23)
The synthesis and structural analysis of polymers dendronized with self-assembling Janus dendrimers containing one fluorinated and one hydrogenated dendrons are reported. Janus dendrimers were attached to the polymer backbone both from the hydrogenated and from the fluorinated parts of the Janus dendrimer. Structural analysis of these dendronized polymers and of their precursors by a combination of differential scanning calorimetry, X-ray diffraction experiments on powder and oriented fibers, and electron density maps have demonstrated that in both cases the dendronized polymer consists of a vesicular columnar structure containing fluorinated alkyl groups on its periphery. This vesicular columnar structure is generated by a mechanism that involves the intramolecular assembly of the Janus dendrimers into tapered dendrons followed by the intramolecular self-assembly of the resulting dendronized polymer in a vesicular column. By contrast with conventional polymers dendronized with self-assembling tapered dendrons this new class of dendronized polymers acts as thermal actuators that decrease the length of the supramolecular column when the temperature is increased and therefore, are called reverse thermal actuators. A mechanism for this reversed process was proposed.
Coassembly of a hexagonal columnar liquid crystalline superlattice from polymer(s) coated with a three-cylindrical bundle supramolecular dendrimer
Percec, Virgil,Ahn, Cheol-H.,Bera, Tushar K.,Ungar, Goran,Yeardley, Duncan J.P.
, p. 1070 - 1083 (2007/10/03)
The synthesis and structural analysis of a polymer containing twin- dendritic benzamide side-groups (i.e. poly{N-[3,4-bis(n-dodecan-1-yloxy)- 5(1-methacryloyl-η-undecan-1-yloxy)phenyl]-3,4,5-tris(n-dodecan-1- yloxy)benzamide}) (19) are described. The disc
