High‐pressure Raman spectroscopy of nanoparticle polyacetylene in a poly(vinyl‐butyral) matrix

Abstract

The pressure-induced Raman shifts of six vibrational bands of 20% and 50% trans-polyacetylene nanoparticles in poly(vinylbutyral) matrix films (NPA/PVB) were studied from 0 to 45 kbar using a diamond anvil cell (DAC). The Raman shifts did not depend on the thickness of the two samples studied. Two of the vibrational bands displayed peak positions that depended on the isomeric compositions, with the 20% trans-NPA/PVB bands being slightly blue-shifted relative to the 50% trans-NPA/PVB bands over the 45 kbar pressure range. The Raman bands of NPA/PVB associated with the trans form initially exhibited a relatively large shift at low pressures (P < 10 kbar) along with a drastic change in their band profile. In order to investigate the relative shielding of the vibrational modes studied, a Grüneisen analysis of the pressure-induced shifts was conducted by estimating the parameters of the Murnaghan equation of state for solid polyacetylene (PA). Four of the six vibrational modes were found to be sensitive to compression of the interchain void space, while the other two modes were insensitive, indicating that they are relatively shielded from the compression of the sample.

High Pressure Polymerization in a Confined Space: Conjugated Chain/Zeolite Nanocomposites

“…Nevertheless, the strong resonance Raman spectrum of PA was always clearly observed, which in turn demonstrates that the chains were conjugated as Raman resonance is indeed related to the presence of conjugation. 48,49 In bulk PA, between 750 cm −1 and 1800 cm −1 , we observe up to seven very strong Raman peaks assigned to different modes of the cis and trans PA isomers 48,49 (Figure 2). In confined PA, i.e.…”

Boron nitride quantum dots/polyvinyl butyral nanocomposite films for the enhanced photoluminescence and UV shielding properties

“…In Figure 4d, micro Raman spectrum of neat polymer film and BNQDs doped composite films were given. Bands at around 1437–1441 cm −1 are due to the CC double bond stretching of PVB polymer 34 . It is observed that as the loading concentration of BNQDs increases, the peak intensities also increase significantly.…”

“…Bands at around 1437-1441 cm À1 are due to the C C double bond stretching of PVB polymer. 34 It is observed that as the loading concentration of BNQDs increases, the peak intensities also increase significantly. The main reason is the structural deformations of the oxygen-rich groups in BNQDs.…”

A nanoparticulate polyacetylene-supported Pd(II) catalyst combining the advantages of homogeneous and heterogeneous catalysts

“…3(b), the Raman spectrum of NP-Pd(II) displays two intense peaks, at 1260 and 423 cm −1 . The band at 423 cm −1 is assigned to the Pd-C=C stretching mode, while the peak at 1260 cm −1 is attributed to the strongly coupled C-C and C=C stretching modes [37,38]. The weak peak at 274 cm −1 is assigned to the Pd-Cl stretching mode [39].…”