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Characterization of free volume and density gradients of polystyrene surfaces by low-energy positron lifetime measurements

Algers, John LU ; Suzuki, R; Ohdaira, T and Maurer, Frans LU (2004) In Polymer 45(13). p.4533-4539
Abstract
Free volume and density gradient widths of the free surface of high molecular mass polystyrene was characterized by use of a pulsed low-energy positron lifetime beam. A density gradient in terms of mass density (g/cm(3)) versus depth (nm) was obtained from the experimental beam data using a novel approach, yielding a width of the density gradient of approximately 3.5 nm. The procedure accounted for the broadening of the positron implantation probe as a function of energy as well as correcting for the increase in positron implantation depths due to the presence of a lower density at the surface region. Moreover, the spectra in the low implantation energy range were found to contain a long-lived lifetime that yielded very large estimates of... (More)
Free volume and density gradient widths of the free surface of high molecular mass polystyrene was characterized by use of a pulsed low-energy positron lifetime beam. A density gradient in terms of mass density (g/cm(3)) versus depth (nm) was obtained from the experimental beam data using a novel approach, yielding a width of the density gradient of approximately 3.5 nm. The procedure accounted for the broadening of the positron implantation probe as a function of energy as well as correcting for the increase in positron implantation depths due to the presence of a lower density at the surface region. Moreover, the spectra in the low implantation energy range were found to contain a long-lived lifetime that yielded very large estimates of the free volume effects at the surface. Accounting for this lifetime in the evaluation procedure, resulted in a much improved agreement with the results of other experimental and theoretical investigations in the literature. (C) 2004 Elsevier Ltd. All rights reserved. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Polymer
volume
45
issue
13
pages
4533 - 4539
publisher
Elsevier
external identifiers
  • wos:000221836600021
  • scopus:2542478169
ISSN
0032-3861
DOI
10.1016/j.polymer.2004.04.008
language
English
LU publication?
yes
id
ca682eab-dd8f-4513-993a-f65e14dc6c71 (old id 139515)
date added to LUP
2007-06-26 11:25:08
date last changed
2017-12-17 03:54:36
@article{ca682eab-dd8f-4513-993a-f65e14dc6c71,
  abstract     = {Free volume and density gradient widths of the free surface of high molecular mass polystyrene was characterized by use of a pulsed low-energy positron lifetime beam. A density gradient in terms of mass density (g/cm(3)) versus depth (nm) was obtained from the experimental beam data using a novel approach, yielding a width of the density gradient of approximately 3.5 nm. The procedure accounted for the broadening of the positron implantation probe as a function of energy as well as correcting for the increase in positron implantation depths due to the presence of a lower density at the surface region. Moreover, the spectra in the low implantation energy range were found to contain a long-lived lifetime that yielded very large estimates of the free volume effects at the surface. Accounting for this lifetime in the evaluation procedure, resulted in a much improved agreement with the results of other experimental and theoretical investigations in the literature. (C) 2004 Elsevier Ltd. All rights reserved.},
  author       = {Algers, John and Suzuki, R and Ohdaira, T and Maurer, Frans},
  issn         = {0032-3861},
  language     = {eng},
  number       = {13},
  pages        = {4533--4539},
  publisher    = {Elsevier},
  series       = {Polymer},
  title        = {Characterization of free volume and density gradients of polystyrene surfaces by low-energy positron lifetime measurements},
  url          = {http://dx.doi.org/10.1016/j.polymer.2004.04.008},
  volume       = {45},
  year         = {2004},
}