Structural and electrical characterization of hybrid metal-polypyrrole nanowires

We present here the synthesis and structural characterization of hybrid Au-polypyrrole-Au and Pt- polypyrrole-Au nanowires together with a study of their electrical properties from room-temperature down to very low temperature. A careful characterization of the metal-polymer interfaces by trans- mission electron microscopy revealed that the structure and mechanical strength of bottom and upper interfaces are very different. Variable temperature electrical transport measurements were performed on both multiple nanowires - contained within the polycarbonate template - and single nanowires. Our data show that the three-dimensional Mott variable-range-hopping model provides a complete framework for the understanding of transport in PPy nanowires, including non-linear current-voltage characteristics and magnetotransport at low temperatures.Comment: Phys. Rev. B Vol. 76 Issue 11 (2007

Mechanical properties of nanotubes of polyelectrolyte multilayers

The elastic properties of nanotubes fabricated by layer-by-layer (LbL) assembly of polyelectrolytes in the nanopores of polycarbonate track-etched membranes have been investigated by resonant contact Atomic Force Microscopy (AFM), for nanotube diameters in the range of 100 to 200 nm. The elastic modulus of the nanotubes was computed from the resonance frequencies of a cantilever resting on freely suspended LbL nanotubes. An average value of 115MPa was found in air for Young's modulus of these nanostructures, well below the values reported for dry, flat multilayers, but in the range of values reported for water-swollen flat multilayers. These low values are most probably due to the lower degree of ionic cross-linking of LbL nanotubes and their consequently higher water content in air, resulting from the peculiar mode of growth of nanoconfined polyelectrolyte multilayers

Electrosynthesis of polypyrrole nanotubules using particle track-etched membranes as template

Polypyrrole has been electrochemically synthesized inside the pores of nanoporous polycarbonate particle track-etched membranes. The morphology and the electrochemical properties of the obtained nanomaterials, using two types of doping anions (poly (sodium-4-styrenesulfonate) and lithium perchlorate) has been studied

Polymer Blends of Polymethylphenylsilane With Polystyrene and Thermal-properties of Polymethylphenylsilane

In attempting to melt blend polymethylphenylsilane (PMPS) and polystyrene, an unusual morphology was observed which led to a more detailed examination of the thermal and physical properties of PMPS. Thermogravimetric analysis shows that PMPS is stable under the conditions used for the melt mixing. For apparently the first time, the results of differential scanning calorimetry, dynamic mechanical thermal analysis and thermomechanical analysis art reported for PMPS. The curves obtained by these three techniques exhibit two thermal transitions at temperatures which are strongly molecular weight dependent. Optical microscopy and X-ray diffraction results show some evidence of the existence of long range ordered regions in PMPS. From the combination of thermal, microscopic and X-ray diffraction results, we assigned the first thermal transition to a glass transition and the second one, occurring at high temperature, to a phase-disordering transition accompanied by the softening of the polymer