Development of Pulsating Tubules with Chiral Inversion
Final rept. 16 Aug 2012-15 Aug 2013
SEOUL NATIONAL UNIV (REPUBLIC OF KOREA)
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Stimuli responsive nanostructures constructed from rigid-flexible block molecules hold great promise for fabrication of intelligent nanodevices, nanoelectronics, and nanobiomaterials. One typical feature of rod amphiphiles is their unique anisotropic molecular shape and strong aggregation tendency through pi-pi stacking interactions, which has enabled construction of highly versatile and dynamic nanostructures. Variations in molecular structure and local environment, albeit small, allow the rapid transformation of equilibrium morphology. This research project involved development of stimuli-responsive nanomaterials using self-assembly of amphiphilic molecules based on hydrophilic oligoethylene glycol chains and hydrophobic aromatic rods and peptides. Pyridine end-substituted rod-coil block systems were found to self-assemble into flat sheets in dilute aqueous solution, but through reversible coordination interaction with Ag1 could change their shape into helical tubules at higher and discrete macrocycles at lower concentrations. Metal-containing macrocycles were found to reversibly stack to form helical tubules in response to variation in concentration. The influence of interactions with small molecule planer aromatics on 2D structure was examined. Rationally designed macrobicyclic amphiphiles consisting of a hydrophilic dendron attached to the center of an aromatic plane undergoes self-assembly into a 2D structure with nanosized lateral pores through lateral association of amphiphile dimers with a uniform diameter of 3.5 nm. The porous sheets efficiently intercalate flat aromatic molecules, such as coronene, through the conformational inversion of the basal planes of the dimeric micelles. This project also examined a novel approach to make short peptides adopt stable alpha-helical structures through macrocyclization of their linear precursors.
- Physical Chemistry
- Polymer Chemistry