Molecular self-assembly is the basis for the formation of numerous artificial nanostructures. The self-organization of peptides, amphiphilic molecules composed of fused benzene rings and other functional molecules into nanotubes is of particular interest. However, the design of dynamic, complex self-organized systems that are responsive to external stimuli remains a significant challenge. Here, we report self-assembled, vesicle-capped nanotubes that can be selectively disassembled by irradiation. The walls of the nanotubes are 3-nm-thick bilayers and are made from amphiphilic molecules with two hydrophobic legs that interdigitate when the molecules self-assemble into bilayers. In the presence of phospholipids, a phase separation between the phospholipids and the amphiphilic molecules creates nanotubes, which are end-capped by vesicles that can be chemically altered or removed and reattached without affecting the nanotubes. The presence of a photoswitchable and fluorescent core in the amphiphilic molecules allows fast and highly controlled disassembly of the nanotubes on irradiation, and distinct disassembly processes can be observed in real time using fluorescence microscopy.

Two types of graphene-based hybrid materials, graphene-TPP (TPP=tetraphenylporphyrin) and graphene-PdTPP (PdTPP=palladium tetraphenylporphyrin), were prepared directly from pristine graphene through one-pot cycloaddition reactions. The hybrid materials were characterized by thermogravimetric analysis (TGA), by TEM, by UV/Vis, FTIR, Raman, and luminescence spectroscopy, and by fluorescence/phosphorescence lifetime measurements. The presence of the covalent linkages between graphene and porphyrin was confirmed by FTIR and Raman spectroscopy and further supported by control experiments. The presence of TPP (or PdTPP) in the hybrid material was demonstrated by UV/Vis spectroscopy, with TGA results indicating that the graphene-TPP and graphene-PdTPP hybrid materials contained approximately 18 % TPP and 20 % PdTPP. The quenching of fluorescence (or phosphorescence) and reduced lifetimes suggest excited state energy/electron transfer between graphene and the covalently attached TPP (or PdTPP) molecules.

Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.

Supporting Information. Details of synthesis and characterization, FTIR, Raman, and XPS spectra, electrochemistry, and procedures for preparation of substrates. This material is available free of charge via the Internet at http://pubs.acs.org.

No abstract