Electronic properties of polymers. Anisotropic light absorption and photoelectron emission of oriented polyethylene films in the vacuum ultraviolet region

Hashimoto, S; Seki, Kazuhiko; Sato, Naoki; Inokuchi, Hiroo

doi:10.1063/1.442755

Cited by 40 publications

(17 citation statements)

References 39 publications

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“…The energy of the E3 peaks in the alkyl-substituted polysilanes corresponds closely to the observed transition energies of polyethylene reported in Table 1 and in the literature [22]. They also correspond reasonably with the reported VUV absorption energies for the E~ peak of normal paraffin hydrocarbons [23] and perflouro-normal paraffins [24], even though the comparable E 3 transition energy in these gas-phase molecules was found to shift to lower energies with increasing carbon content.…”

Section: Sidechain E3 Transitionssupporting

confidence: 90%

Vacuum ultraviolet spectroscopy of the optical properties and electronic structure of seven poly(di-alkylsilanes)

et al. 1992

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We report the ultraviolet (UV) and vacuum ultraviolet (VUV) optical properties and electronic structure, up to 44 eV, of thin-film samples of seven poly(di-alkylsilanes) [alkyl=n-butyl, n-pentyl, i-hexyl, n-hexyl, n-octyl, and n-tetradecyl] with three types of Si-Si backbone conformations: helical, planar zigzag, and trans-gauche--tra~s-gauche' (TGTG'). The backbone conformation determines the UV transitions, with helical materials exhibiting one near-UV absorption, while two UV transitions are seen for the two-phase materials containing both the helical and planar zigzag backbone conformations. The TGTG' backbone exhibits a single UV absorption at 3.6 eV. At higher energies all materials show a prominent shoulder at 7.2 eV, with a doublet peak structure seen at ~9 and 12 eV. The 7.2 eV transition is unaffected by the backbone conformation or alkyl substitution, while comparison with the electronic transitions in polyethylene shows that the high-energy double-peak structure corresponds to transitions in the hydrocarbon sidechains. The ~ 12 eV transitions appear to shift to higher energy with increasing sidechain length and in tetradecyl these sidechaln transitions are noticeably narrowed, suggesting unusual sidechain crystallization in poly(di-n-tetradecylsilane). A hierarchy of electronic transitions can be developed whereby the UV transitions arise in the Si backbone, at intermediate energies backbone to sidechain transitions are observed, while the highenergy transitions are of the alkyl sidechains. This hierarchy in the electronic transitions demonstrates the ability of VUV spectroscopy of the electronic structure to serve as a microscopic probe of the bonding and structure of polysilanes, for example providing detailed insight into the properties of the sidechains in these polymers.

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Section: Sidechain E3 Transitionssupporting

confidence: 90%

Vacuum ultraviolet spectroscopy of the optical properties and electronic structure of seven poly(di-alkylsilanes)

et al. 1992

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“…28 found for anisotropic electron absorption spectra of polyethylene that the calculated polarization of the two lowest transitions agrees with the experiment only when the ab initio method was used.…”

Section: K=lmentioning

confidence: 87%

“…Recently, anisotropic absorption in polyethylene in the vacuum ultraviolet region was reported by Hashimoto et a/. 28 The anisotropy of light absorption is common to linear polymers in any wavelength region.…”

Section: Polarized Absorption Spectramentioning

confidence: 96%

Anisotropic Absorption and Reflection Spectra of Poly(ethylene terephthalate) Films in Ultraviolet Region

Ouchi

1983

Polym J

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ABSTRACT:Thin uniaxially drawn poly( ethylene terephthalate) films (down to 0.1 flm thickness) were prepared. Their absorption spectra showed clear dichroism having peaks at 300 (.l), 243 (/ /) and 197 nm (/ 1). Analysis of the reflection spectra of thick films by means of the Kramers-Kronig conversion gave absorption spectra almost identical with those obtained from direct absorption measurement. Spectral shapes and possible origins of the vibrational structures were qualitatively discussed. The oscillator strength of each band was obtained on the simple oriented gas model with or without the Lorentz field correction to examine effects of molecular aggregation. PPP calculations with CI were made by use of a model compound, and four 1 A•-> 1 Bu allowed transitions were predicted to occur at 4.66, 5.27, 6.33 and 6.44eV. The latter two transitions were actually observed at 6.2eV. The calculated transition moments suggested the existence of the cis form of carbonyl groups in oriented amorphous phases.

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“…There are prior reports on the electronic excitations and optical transitions of various polymers over limited energy ranges such as poly(methyl methacrylate) (PMMA), [15,16] bisphenol A polycarbonate (PC), [17] low-density polyethylene (LDPE), [18] and from 250 to 170 nm on polyethylene (PE), polytetrafluoroethylene (PTFE), styrene allyl alcohol (SAA), and other polymers. [19] We previously studied seven different poly(dialkylsilanes) [20,21] using quantitative analysis of vacuum ultraviolet (VUV) reflectance measurements to determine the interband transition strength (J cv ) so as to develop a hierarchy of the optical excitations in these silicon backbone polymers.…”

Section: Electronic Structure and Optical Properties Of Polymersmentioning

confidence: 99%

Optical Properties and van der Waals - London Dispersion Interactions of Polystyrene Determined by Vacuum Ultraviolet Spectroscopy and Spectroscopic Ellipsometry

et al. 2007

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The interband optical properties of polystyrene in the vacuum ultraviolet (VUV) region have been investigated using combined spectroscopic ellipsometry and VUV spectroscopy. Over the range 1.5-32 eV, the optical properties exhibit electronic transitions we assign to three groupings, E 1 , E 2 , and E 3 , corresponding to a hierarchy of interband transitions of aromatic (π → π*), non-bonding (n → π*, n → σ*), and saturated (σ → σ*) orbitals. In polystyrene there are strong features in the interband transitions arising from the side-chain π bonding of the aromatic ring consisting of a shoulder at 5.8 eV (E 1 ) and a peak at 6.3 eV (E 1 ), and from the σ bonding of the C-C backbone at 12 eV (E 3 ) and 17.1 eV (E 3 ). These E 3 transitions have characteristic critical point line shapes associated with one-dimensionally delocalized electron states in the polymer backbone. A small shoulder at 9.9 eV (E 2 ) is associated with excitations possibly from residual monomer or impurities. Knowledge of the valence electronic excitations of a material provides the necessary optical properties to calculate the van der Waals-London dispersion interactions using Lifshitz quantum electrodynamics theory and full spectral optical properties. Hamaker constants and the van der Waals-London dispersion component of the surface free energy for polystyrene were determined. These Lifshitz results were compared to the total surface free energy of polystyrene, polarity, and dispersive component of the surface free energy as determined from contact angle measurements with two liquids, and with literature values. The Lifshitz approach, using full spectral Hamaker constants, is a more direct determination of the van der Waals-London dispersion component of the surface free energy of polystyrene than other methods.

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Electronic properties of polymers. Anisotropic light absorption and photoelectron emission of oriented polyethylene films in the vacuum ultraviolet region

Cited by 40 publications

References 39 publications

Vacuum ultraviolet spectroscopy of the optical properties and electronic structure of seven poly(di-alkylsilanes)

Vacuum ultraviolet spectroscopy of the optical properties and electronic structure of seven poly(di-alkylsilanes)

Anisotropic Absorption and Reflection Spectra of Poly(ethylene terephthalate) Films in Ultraviolet Region

Optical Properties and van der Waals - London Dispersion Interactions of Polystyrene Determined by Vacuum Ultraviolet Spectroscopy and Spectroscopic Ellipsometry

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