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X-ray standing waves: a molecular yardstick for biological membranes
M J Bedzyk1, D H Bilderback, G M Bommarito
1Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, NY 14853.
Science (New York, N.Y.)
|September 30, 1988
Summary
Atomic-scale structural information was obtained for a Langmuir-Blodgett (LB) trilayer using x-ray standing waves. Researchers observed a 30 A inward collapse of the zinc atom layer within the LB system.
Area of Science:
- Materials Science
- Surface Science
- Nanotechnology
Background:
- Langmuir-Blodgett (LB) films enable precise layer-by-layer deposition of molecules.
- Understanding atomic arrangements in LB films is crucial for advanced material applications.
- Layered synthetic microstructures (LSMs) serve as well-defined substrates for thin film studies.
Purpose of the Study:
- To determine the atomic-scale structure of an LB trilayer system.
- To investigate the structural response of an LB film under specific conditions.
- To precisely measure atomic layer positions and dimensions.
Main Methods:
- Utilized long-period x-ray standing waves to probe atomic structure.
- Deposited a zinc and cadmium arachidate LB trilayer onto a tungsten/silicon LSM.
- Analyzed x-ray reflectivity data to determine atomic layer positions.
Main Results:
- Observed a significant inward collapse (30 A) of the zinc atom layer.
- The zinc atom layer was initially positioned 53 A above the LSM surface.
- Determined the mean position and width of the zinc layer with +/- 0.3 A precision.
Conclusions:
- Demonstrated the capability of x-ray standing waves for atomic-scale structural analysis of LB films.
- Revealed a thermally induced structural rearrangement in the zinc arachidate layer.
- Provided precise structural data essential for the design and fabrication of nanoscale devices.