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

Journal Article · Thu Aug 22 04:00:00 EDT 1991 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100170a046· OSTI ID:7265852

Schlossman, M L; Schwartz, D K; Kawamoto, E H; Kellogg, G J; Pershan, P S ^[1]; Kim, M W ^[2]; Chung, T C ^[3]

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1. Harvard Univ., Cambridge, MA (United States)
2. Exxon Research and Engineering Co., Annandale, NJ (United States)
3. Pennsylvania State Univ., University Park (United States)

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 {angstrom}{sup {minus}1}, to Q{sub z} {approx equal} 0.6 {angstrom}{sup {minus}1} (where Q{sub z} 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 p(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 {approximately}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.

• DOE Contract Number: AC02-76CH00016
• OSTI ID: 7265852
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 95:17; ISSN JPCHA; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ALCOHOLS
DATA
DENSITY
ELECTRON DENSITY
EXPERIMENTAL DATA
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
INFORMATION
INTERFACES
ISOTHERMS
LAYERS
MATHEMATICAL MODELS
NUMERICAL DATA
OPTICAL PROPERTIES
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
POLYMERS
REFLECTIVITY
SATURATION
SPECTRA
SURFACE PROPERTIES
THEORETICAL DATA
WATER
X-RAY SPECTRA