Preparation, structure and properties of uniaxially oriented polyethylene-silver nanocomposites

Uniaxially oriented composites of high-density polyethylene and silver nanoparticles were prepared using solution-casting, melt-extrusion and solid-state drawing techniques. The absorption spectrum in the visible wavelength range of the drawn nanocomposites was observed to strongly depend on the polarisation direction of the incident light. For instance, the nanocomposites appear bright yellow or red when the vibration direction of linearly polarised light is perpendicular or parallel, respectively, to the drawing axis. The optical anisotropy of the drawn nanocomposites originates from uniaxially oriented, pearl-necklace type of arrays of nanoparticles of high aspect ratios. The absorption spectrum of the nanocomposites can be shifted to higher wavelengths using appropriate annealing procedures. The annealing results in an increased size of the primary silver particles, due to Ostwald ripening, and consequently a range of polarisation-dependent colours can be generated in the drawn nanocomposites

Oriented pearl-necklace arrays of metallic nanoparticles in polymers : a new route toward polarization-dependent color filters

No abstrac

Preparation, structure and properties of uniaxially oriented polyethylene-silver nanocomposites

Uniaxially oriented composites of high-density polyethylene and silver nanoparticles were prepared using solution-casting, melt-extrusion and solid-state drawing techniques. The absorption spectrum in the visible wavelength range of the drawn nanocomposites was observed to strongly depend on the polarisation direction of the incident light. For instance, the nanocomposites appear bright yellow or red when the vibration direction of linearly polarised light is perpendicular or parallel, respectively, to the drawing axis. The optical anisotropy of the drawn nanocomposites originates from uniaxially oriented, pearl-necklace type of arrays of nanoparticles of high aspect ratios. The absorption spectrum of the nanocomposites can be shifted to higher wavelengths using appropriate annealing procedures. The annealing results in an increased size of the primary silver particles, due to Ostwald ripening, and consequently a range of polarisation-dependent colours can be generated in the drawn nanocomposites

Oriented nanocomposites of ultrahigh-molecular-weight polyethylene and gold

Polymer nanocomposites were prepd. by mixing ultrahigh-mol.-wt. polyethylene and gold colloids coated with a self-assembled monolayer of dodecanethiol. Subsequently, these materials were oriented by solid state drawing which induced the formation of uniaxially oriented arrays of gold particles. As a result of the orientation of the gold arrays, the VIS-near IR spectra of the drawn composites strongly depended in polarized light on the angle between polarization direction and the orientation axis of the particle arrays, with shifts in the absorption maxima up to ca. 100 nm. It is assumed that these color shifts originated from the small dimensions of the dispersed metal phase in combination with their uniaxial orientation. [on SciFinder (R)

Growth and anisotropic properties of highly oriented films of quasi-one-dimensional platinum compounds

International audienc

Ultrahigh chiral anisotropy factors in quasi-one-dimensional platinum compounds

Optically active, quasi-one-dimensional Pt-based compds. of the Magnus' green salt type [Pt(NH2R)4][PtCl4] where R denotes (S)-3,7-dimethyloctyl or (R)-2-ethylhexyl were synthesized. The optically active side groups in the corresponding complexes were found to induce CD (CD) in the dz2-pz transition between platinum atoms of adjacent coordination units. Interestingly, a bisignate Cotton effect was obsd., indicative of a helical structure of [Pt(NH2R)4][PtCl4]. The abs. values of the chiral anisotropy factors were of the order of 0.1, which is among the highest values reported for metal complexes. [on SciFinder (R)

Polymers and metals; nanocomposites and complex salts with metallic chain structure

No abstract available

A soluble equivalent of the supramolecular, quasi-one-dimensional, semiconducting Magnus' green salt

A soluble supramolecular, quasi-one-dimensional semiconducting complex comprising alternately stacked [Pt(NH(2)dmoc)(4)](2+) and [PtCl4](2-) units, where dmoc denotes (S)-3,7-dimethyloctyl, has been synthesized and characterized with various methods. In contrast to earlier enunciated expectations and unlike nearly all other known derivatives, [Pt(NH2dmoc)41 [PtCl4] showed the color of Magnus' green salt, [Pt(NH3)(4)] [PtCl4], which is characteristic for linearly arranged platinum atoms with considerable Pt-Pt interactions. The Pt-Pt distance in [Pt(NH(2)dmoc)(4)] [PtCl4] was established to be 3.1 Angstrom from powder X-ray and electron diffraction patterns. Similar to Magnus' green salt, [Pt(NH(2)dmoc)(4)] [PtCl4] was found to be a semiconductor with a thermal activation energy of 0.24 eV and an electrical conductivity of 1.6 x 10(-7) S/cm at room temperature, Although Magnus' green salt virtually is intractable, [Pt(NH(2)dmoc)(4)] [PtCl4] was soluble in common organic solvents. Remarkably, strong evidence indicated that self-assembled platinum chain structures were present also in solution. Hence, [Pt(NH(2)dmoc)(4)][PtCl4] may indeed be regarded as a processible form of Magnus' green sal