Aligned 1-D nanorods of a π-gelator exhibit molecular orientation and excitation energy transport different from entangled fiber networks.

Linear π-gelators self-assemble into entangled fibers in which the molecules are arranged perpendicular to the fiber long axis. However, orientation of gelator molecules in a direction parallel to the long axes of the one-dimensional (1-D) structures remains challenging. Herein we demonstrate that, at the air-water interface, an oligo(p-phenylenevinylene)-derived π-gelator forms aligned nanorods of 340 ± 120 nm length and 34 ± 5 nm width, in which the gelator molecules are reoriented parallel to the long axis of the rods.

Facile fabrication of silver nanoclusters as promising surface-enhanced Raman scattering substrates.

We present a simple wet chemical method to make thin film of silver nanoclusters on glass or silicon substrate. The method includes immersion of glass or silicon substrate into a saturated solution of silver nitrate in n-octanol. After 24 h, thin film of silver nanoclusters, which are micrometer-scale aggregates of silver nanoparticles with average size in the range of 80-100 nm, are formed on the substrate.

Hydrogen-bond-driven 'homogeneous intercalation' for rapid, reversible, and ultra-precise actuation of layered clay nanosheets.

The use of hydrogen bonds permits a fluidic motion of differently sized alcohol molecules across the interlayer gap in LDH, which enables rapid and reversible tuning of interlayer spacing of the LDH at sub-Ångström precision by changing the mole ratio of the different alcohols.

Langmuir nanoarchitectonics: one-touch fabrication of regularly sized nanodisks at the air-water interface.

In this article, we propose a novel methodology for the formation of monodisperse regularly sized disks of several nanometer thickness and with diameters of less than 100 nm using Langmuir monolayers as fabrication media. An amphiphilic triimide, tri-n-dodecylmellitic triimide (1), was spread as a monolayer at the air-water interface with a water-soluble macrocyclic oligoamine, 1,4,7,10-tetraazacyclododecane (cyclen), in the subphase. The imide moieties of 1 act as hydrogen bond acceptors and can interact weakly with the secondary amine moieties of cyclen as hydrogen bond donors.

Controlling porphyrin nanoarchitectures at solid interfaces.

Two complementary examples of porphyrin nanoarchitectonics are presented. The fabrication of binary molecular monolayers using two different porphyrin molecules, tetrakis(3,5-di-t-butyl-4-hydroxyphenyl)porphyrin (1) and tetrakis(4-pyridyl)porphyrin (2), by deposition in ultrahigh vacuum was demonstrated. Two unusual heteromolecular monolayer structures were observed, with one exhibiting good separation of 1 molecules within the monolayer.

Paradigm shift from self-assembly to commanded assembly of functional materials: recent examples in porphyrin/fullerene supramolecular systems.

Current nanotechnology based on top-down nanofabrication may encounter a variety of drawbacks in the near future so that development of alternative methods, including the so-called bottom-up approach, has attracted considerable attention. However, the bottom-up strategy, which often relies on spontaneous self-assembly, might be inefficient in the development of the requisite functional materials and systems. Therefore, assembly processes controlled by external stimuli might be a plausible strategy for the development of bottom-up nanotechnology.

Anchoring of self-assembled monolayers of unsymmetrically-substituted chromophores with an oxoporphyrinogen surface clamp.

Multichromophoric molecules of conjugated N-substituted oxoporphyrinogens have been assembled on the Au(111) surface using solution and sublimation techniques. The operation of the oxoporphyrinogen moiety as a surface anchoring unit in the formation of molecular monolayers has been demonstrated.

Electrochemical-coupling layer-by-layer (ECC-LbL) assembly.

Electrochemical-coupling layer-by-layer (ECC-LbL) assembly is introduced as a novel fabrication methodology for preparing layered thin films. This method allows us to covalently immobilize functional units (e.g.

Self-assembled pyrazinacene nanotubes.

Nanotubes of a pentacene derivative, 6,13-bis(1-n-dodecyl)-[a,c,l,n]-tetrabenzo-5,6,7,12,13,14-hexaazapentacene, have been prepared by a hierarchical self-assembly mechanism. The oligoazaacenes 1-3, referred to as pyrazinacenes due to their structures of linearly fused pyrazine heterocycles, can also be considered as two azatriphenylenes fused through a reduced pyrazine ring. Dissolution of 6,13-bis(1-n-dodecyl)-[a,c,l,n]-tetrabenzo-5,6,7,12,13,14-hexaaza pentacene in nearly boiling toluene followed by standing of the solution at room temperature yields self-assembled (sa) pyrazinacene (Pa) nanotubes (NT's), or sa-PaNTs.

Real time self-assembly and reassembly of molecular nanowires of trigeminal amphiphile porphyrins.

Self-assembly and reassembly of high aspect ratio nanowires of trigeminal porphyrins and their manipulation using an atomic force microscope (AFM) is reported.

Block-copolymer-nanowires with nanosized domain segregation and high charge mobilities as stacked p/n heterojunction arrays for repeatable photocurrent switching.

Development of materials for efficient photoenergy conversion is a subject of critical importance in current science and technology. Efficient performance requires well-controlled segregation of electron donor and acceptor moieties, which we have achieved using block copolymers of tetraphenylporphinatozinc(II) (donor) and C(60) fullerene (acceptor) using living ring-opening metathesis polymerization (ROMP). The resulting amphiphilic ROMP block copolymers undergo self-assembly into nanostructured phase-segregated 1-dimensional nanowires with an approximately 5.

Evidence for a ball-shaped cyclen cyclophane: an experimental and first principles study.

Conformational isomerism of a ball-shaped cyclophane of cyclen was studied using NMR and computational methods with the most notable conformer containing a highly symmetric cyclic benzene tetramer.

Diverse self-assembly in soluble oligoazaacenes: a microscopy study.

The synthesis and morphologies of self-assembled aggregates of novel oligoazapentacene 2 and oligoazaheptacene 3 derivatives are reported. Double nucleophilic substitution on 2,3-dicyano-[h,j]-dibenzo-1,4,5,10-tetrazaanthracene 4 gives the corresponding dihydro-oligoacene derivatives, which were then N-alkylated using n-dodecyl bromide to yield self-assembling acene molecules. 2 and 3 self-assemble in solution, leading to a variety of aggregated structures including rolled-up sheets, foams, and fibrous structures reminiscent of organogels.