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Small angle neutron scattering on an absolute intensity scale and the internal surface of diatom frustules from three species of differing morphologies

Garvey, C. J.; Strobl, Markus LU ; Percot, A.; Saroun, J.; Haug, J.; Vyverman, W.; Chepurnov, V. A. and Ferris, J. M. (2013) In European Biophysics Journal 42(5). p.395-404
Abstract
The internal nanostructure of the diatoms Cyclotella meneghiniana, Seminavis robusta and Achnanthes subsessilis was investigated using small angle neutron scattering (SANS) to examine thin biosilica samples, consisting of isotropic (powder) from their isolated cell walls. The interpretation of SANS data was assisted by several other measurements. The N-2 adsorption, interpreted within the Branuer-Emmet-Teller isotherm, yielded the specific surface area of the material. Fourier transform infrared (FTIR) and Raman spectroscopy indicates that the isolated material is amorphous silica with small amounts of organic cell wall materials acting as a filling material between the silica particles. A two-phase (air and amorphous silica) model was... (More)
The internal nanostructure of the diatoms Cyclotella meneghiniana, Seminavis robusta and Achnanthes subsessilis was investigated using small angle neutron scattering (SANS) to examine thin biosilica samples, consisting of isotropic (powder) from their isolated cell walls. The interpretation of SANS data was assisted by several other measurements. The N-2 adsorption, interpreted within the Branuer-Emmet-Teller isotherm, yielded the specific surface area of the material. Fourier transform infrared (FTIR) and Raman spectroscopy indicates that the isolated material is amorphous silica with small amounts of organic cell wall materials acting as a filling material between the silica particles. A two-phase (air and amorphous silica) model was used to interpret small angle neutron scattering data. After correction for instrumental resolution, the measurements on two SANS instruments covered an extended range of scattering vectors 0.0011 nm(-1) < q < 5.6 nm(-1), giving an almost continuous SANS curve over a range of scattering vectors, q, on an absolute scale of intensity for each sample. Each of the samples gave a characteristic scattering curve where log (intensity) versus log (q) has a -4 dependence, with other features superimposed. In the high-q regime, departure from this behaviour was observed at a length-scales equivalent to the proposed unitary silica particle. The limiting Porod scattering law was used to determine the specific area per unit of volume of each sample illuminated by the neutron beam. The Porod behaviour, and divergence from this behaviour, is discussed in terms of various structural features and the proposed mechanisms for the bio-assembly of unitary silica particles in frustules. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Biosilica, Diffusion limited aggregation, Small angle neutron, scattering, Raman spectroscopy, Infrared spectroscopy, Porod law, BET, isotherm, Biomineralisation
in
European Biophysics Journal
volume
42
issue
5
pages
395 - 404
publisher
Springer
external identifiers
  • wos:000319221400008
  • scopus:84877835733
ISSN
0175-7571
DOI
10.1007/s00249-013-0889-x
language
English
LU publication?
yes
id
4cfd9451-95a9-4a7d-a177-c0c475b05f7d (old id 3932248)
date added to LUP
2013-07-15 13:43:51
date last changed
2018-05-29 12:14:31
@article{4cfd9451-95a9-4a7d-a177-c0c475b05f7d,
  abstract     = {The internal nanostructure of the diatoms Cyclotella meneghiniana, Seminavis robusta and Achnanthes subsessilis was investigated using small angle neutron scattering (SANS) to examine thin biosilica samples, consisting of isotropic (powder) from their isolated cell walls. The interpretation of SANS data was assisted by several other measurements. The N-2 adsorption, interpreted within the Branuer-Emmet-Teller isotherm, yielded the specific surface area of the material. Fourier transform infrared (FTIR) and Raman spectroscopy indicates that the isolated material is amorphous silica with small amounts of organic cell wall materials acting as a filling material between the silica particles. A two-phase (air and amorphous silica) model was used to interpret small angle neutron scattering data. After correction for instrumental resolution, the measurements on two SANS instruments covered an extended range of scattering vectors 0.0011 nm(-1) &lt; q &lt; 5.6 nm(-1), giving an almost continuous SANS curve over a range of scattering vectors, q, on an absolute scale of intensity for each sample. Each of the samples gave a characteristic scattering curve where log (intensity) versus log (q) has a -4 dependence, with other features superimposed. In the high-q regime, departure from this behaviour was observed at a length-scales equivalent to the proposed unitary silica particle. The limiting Porod scattering law was used to determine the specific area per unit of volume of each sample illuminated by the neutron beam. The Porod behaviour, and divergence from this behaviour, is discussed in terms of various structural features and the proposed mechanisms for the bio-assembly of unitary silica particles in frustules.},
  author       = {Garvey, C. J. and Strobl, Markus and Percot, A. and Saroun, J. and Haug, J. and Vyverman, W. and Chepurnov, V. A. and Ferris, J. M.},
  issn         = {0175-7571},
  keyword      = {Biosilica,Diffusion limited aggregation,Small angle neutron,scattering,Raman spectroscopy,Infrared spectroscopy,Porod law,BET,isotherm,Biomineralisation},
  language     = {eng},
  number       = {5},
  pages        = {395--404},
  publisher    = {Springer},
  series       = {European Biophysics Journal},
  title        = {Small angle neutron scattering on an absolute intensity scale and the internal surface of diatom frustules from three species of differing morphologies},
  url          = {http://dx.doi.org/10.1007/s00249-013-0889-x},
  volume       = {42},
  year         = {2013},
}