X-ray reflectivity of a polymer monolayer at the water/vapor interface

M. L. Schlossman, D. K. Schwartz, E. H. Kawamoto, G. J. Kellogg, P. S. Pershan, M. W. Kim, Tze-chiang Chung

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Abstract

X-ray specular reflectivity from a monolayer of partially hydroxylated 1,2-polybutadiene (50% butyl alcohol random substitution) at the water/vapor interface was measured from below the critical wavevector for water, 0.0217 Å-1, to Qz ≅ 0.6 Å-1 (where Qz is the transferred momentum normal to the interface). The sample was prepared on a Langmuir trough, and measurements were made at five different surface densities in the high-pressure, or saturated, region of the isotherm. The measured reflectivity is interpreted to obtain a profile of the average electron density ρ(z) as a function of distance z along the surface normal. The profile has a local maximum that is approximately 10% larger than the electron density in bulk crystalline 1,2-polybutadiene. At the highest pressures the width of the liquid/vapor interface is ∼10% larger than the value calculated from thermal capillary waves using in situ measurements of the surface tension; however, for smaller pressures the measured and calculated values agree.

Original languageEnglish (US)
Pages (from-to)6628-6632
Number of pages5
JournalJournal of physical chemistry
Volume95
Issue number17
DOIs
StatePublished - Jan 1 1991

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All Science Journal Classification (ASJC) codes

  • Engineering(all)
  • Physical and Theoretical Chemistry

Cite this

Schlossman, M. L., Schwartz, D. K., Kawamoto, E. H., Kellogg, G. J., Pershan, P. S., Kim, M. W., & Chung, T. (1991). X-ray reflectivity of a polymer monolayer at the water/vapor interface. Journal of physical chemistry, 95(17), 6628-6632. https://doi.org/10.1021/j100170a046