7 research outputs found
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 materialsboth P4VP and
PS<i>-<i>b</i>-</i>P4VP based complexesby
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