Small-angle Rayleigh scattering by relatively large latex particles

Robert Y. Ofoli, Dennis C. Prieve

Research output: Contribution to journalArticle

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Abstract

According to the Rayleigh-Debye (RG) theory of light scattering, the intensity of forward scattering is proportional to the volume-squared of the scatterers, independent of their shape or orientation. This makes small-angle light scattering (SALS) attractive as a tool for studying the kinetics of flocculation of model latexes, where the conformation of elemental particles in any floe is unknown. In preparation for such a study using a modified version of the apparatus of Lips and Willis (1973), we experimentally determine the limits under which SALS produced by a He-Ne laser can be used for sizing of monodisperse polystyrene latexes. For every particle in the sample volume to experience the same intensity of incident light (i.e. for negligible extinction), the particle concentration must be less than cmax, where cmaxld6=(1.08 ± 0.09) × 10-26 m4, l is the pathlength and d is the particle diameter. For c <cmax, the scattering per particle at 2° is proportional to d6 provided d is less than 1 μm, which is considerably larger than for scattering at larger angles. We speculate that the scattering by flocs will be proportional to the square of the number of elemental particles in dependent of their conformation provided the floe is also smaller than 1 μm.

LanguageEnglish (US)
Pages4837-4842
Number of pages6
JournalLangmuir
Volume13
Issue number18
StatePublished - Sep 3 1997

Profile

Rayleigh scattering
Latex
latex
Latexes
Light scattering
Particles (particulate matter)
Scattering
Conformations
Forward scattering
Light extinction
light scattering
Flocculation
scattering
Polystyrenes
Kinetics
Lasers
sizing
forward scattering
polystyrene
extinction

ASJC Scopus subject areas

  • Colloid and Surface Chemistry
  • Physical and Theoretical Chemistry

Cite this

Small-angle Rayleigh scattering by relatively large latex particles. / Ofoli, Robert Y.; Prieve, Dennis C.

In: Langmuir, Vol. 13, No. 18, 03.09.1997, p. 4837-4842.

Research output: Contribution to journalArticle

Ofoli, Robert Y. ; Prieve, Dennis C./ Small-angle Rayleigh scattering by relatively large latex particles. In: Langmuir. 1997 ; Vol. 13, No. 18. pp. 4837-4842
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