Analysis of Order Formation in Block Copolymer Thin Films UsingResonant Soft X-Ray Scattering
The lateral order of poly(styrene-block-isoprene) copolymer(PS-b-PI) thin films is characterized by the emerging technique ofresonant soft X-ray scattering (RSOXS) at the carbon K edge and comparedto ordering in bulk samples of the same materials measured usingconventional small-angle X-ray scattering. We show resonance using theoryand experiment that the loss of scattering intensity expected with adecrease in sample volume in the case of thin films can be overcome bytuning X-rays to the pi* resonance of PS or PI. Using RSOXS, we study themicrophase ordering of cylinder- and phere-forming PS-b-PI thin films andcompare these results to position space data obtained by atomic forcemicroscopy. Our ability to examine large sample areas (~;9000 mu m2) byRSOXS enables unambiguous identification of the lateral lattice structurein the thin films. In the case of the sphere-forming copolymer thin film,where the spheres are hexagonally arranged, the average sphere-to-spherespacing is between the bulk (body-centered cubic) nearest neighbor andbulk unit cell spacings. In the case of the cylinder-forming copolymerthin film, the cylinder-to-cylinder spacing is within experimental errorof that obtained in the bulk.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Director, Office of Science; National ScienceFoundation
- DOE Contract Number:
- DE-AC02-05CH11231; NSF:DMR-0514422
- OSTI ID:
- 923359
- Report Number(s):
- LBNL-62652; R&D Project: 504103; BnR: KC0202020; TRN: US200804%%1085
- Journal Information:
- Macromolecules, Vol. 40, Issue 6; Related Information: Journal Publication Date: March 2007
- Country of Publication:
- United States
- Language:
- English
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