Reflection and transmission coefficients of nano-metamaterial antennas at microwave frequencies

The hypothesis of this paper is that when metallic nanoparticles are grouped together by suitable field coupling they can behave like larger objects which will resonate at microwave frequencies. This means that sheets of nanomaterials can be designed that are largely transparent at these spectra except where an antenna has been created from densely grouped clusters of metallic nanoparticles. Simulations, based on actual samples composed of nano-metamaterials, show the behaviour of the reflection and transmission coefficients of antennas. The resonant frequency can increase or decrease depending on the geometry

Metallic inclusions in a non-uniform lattice

This paper is part of a larger project which aims to investigate the fabricational and electromagnetic advantages of creating integrated antenna systems using emerging nanomanufacturing technology. It has been known for several decades that the effective permittivity of a mixture consisting of dielectric inclusions in a host dielectric can be controlled by varying the permittivity, size and spacing of the inclusions. Various authors have developed theoretical equations to analyse these structures but are typically limited to spherical inclusions in a uniform cubic lattice. This paper extends this work from spheres in a uniform mesh to investigate thin metallic inclusions in a dielectric host using a non-uniform lattice (spacing in x, y and z, not the same). Electromagnetic simulations of these structures have been compared to canonical equations of spheres in a cubic uniform lattice with the same volume ratio

Photocontrol over Cucurbit[8]uril Complexes: Stoichiometry and Supramolecular Polymers

Herein we report the photocontrol of cucurbit[8]­uril (CB[8])-mediated supramolecular polymerization of azobenzene-containing monomers. The CB[8] polymers were characterized both in solution and in the solid state. These host–guest complexes can be reversibly switched between highly thermostable photostationary states. Moreover, a remarkable stabilization of <i>Z</i>-azobenzene was achieved by CB[8] complexation, allowing for structural characterization in the solid state

Photocontrol over Cucurbit[8]uril Complexes: Stoichiometry and Supramolecular Polymers

Herein we report the photocontrol of cucurbit[8]­uril (CB[8])-mediated supramolecular polymerization of azobenzene-containing monomers. The CB[8] polymers were characterized both in solution and in the solid state. These host–guest complexes can be reversibly switched between highly thermostable photostationary states. Moreover, a remarkable stabilization of <i>Z</i>-azobenzene was achieved by CB[8] complexation, allowing for structural characterization in the solid state

Photocontrol over Cucurbit[8]uril Complexes: Stoichiometry and Supramolecular Polymers

Herein we report the photocontrol of cucurbit[8]­uril (CB[8])-mediated supramolecular polymerization of azobenzene-containing monomers. The CB[8] polymers were characterized both in solution and in the solid state. These host–guest complexes can be reversibly switched between highly thermostable photostationary states. Moreover, a remarkable stabilization of <i>Z</i>-azobenzene was achieved by CB[8] complexation, allowing for structural characterization in the solid state

Photocontrol over Cucurbit[8]uril Complexes: Stoichiometry and Supramolecular Polymers

Herein we report the photocontrol of cucurbit[8]­uril (CB[8])-mediated supramolecular polymerization of azobenzene-containing monomers. The CB[8] polymers were characterized both in solution and in the solid state. These host–guest complexes can be reversibly switched between highly thermostable photostationary states. Moreover, a remarkable stabilization of <i>Z</i>-azobenzene was achieved by CB[8] complexation, allowing for structural characterization in the solid state

Self-Assembly and Photoinduced Optical Anisotropy in Dendronized Supramolecular Azopolymers

Herein we report the preparation and characterization of dendronized supramolecular polymers composed of a carboxy-terminated azodendron, dAZO, and two different vinylpyridine-containing polymers: poly­(4-vinylpyridine) (P4VP) and polystyrene<i>-<i>b</i>-</i>poly­(4-vinylpyridine) (PS<i>-<i>b</i>-</i>P4VP) block copolymer. P4VP can selectively complex dAZO through hydrogen-bonding interactions, thus resulting in liquid crystalline materials. Additionally, this strategy is also applicable to the preparation of dendronized supramolecular block copolymers (BCs). Lamellar, cylindrical, and spherical morphologies are observed for the BC complexes depending on the dAZO to vinylpyridine repeating unit ratio. Photoinduced orientation of the azobenzene moieties is obtained in films of the H-bonded materialsboth P4VP and PS<i>-<i>b</i>-</i>P4VP based complexesby using 488 nm linearly polarized light and characterized through birefringence and dichroism measurements. High and stable values of birefringence are obtained for polymers with azobenzene content as low as 2.7 wt %, thus demonstrating the benefits of preorganization in photoactive dendritic moieties in side-chain H-bonded materials