Molecular surface structure of comb-like polyoxyethylene with alkyl sulfonyl side-chains studied by sum-frequency generation vibrational spectroscopy |
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| Authors: | Inseon Seo Eun-Ho Sohn Jong-Chan Lee Kigook Song Fumito Araoka Ken Ishikawa |
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| Institution: | 1. Department of Organic and Polymeric Materials , Tokyo Institute of Technology , Japan;2. Materials Research Center for Information Display, Kyung Hee University , Yongin , Republic of Korea;3. Materials Research Center for Information Display, Kyung Hee University , Yongin , Republic of Korea;4. Department of Chemical and Biological Engineering , Seoul National University , Republic of Korea;5. Department of Organic and Polymeric Materials , Tokyo Institute of Technology , Japan |
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| Abstract: | The orientation of alkyl sulfonyl side-chains on a series of polyoxyethylenes, CH3–nSE (n?=?6, 8 or 10), and the effect of annealing and rubbing on the molecular orientation of the alkyl side-chains at the substrate surface, were investigated using sum-frequency generation (SFG) vibrational spectroscopy. Based on the SFG spectra and their quantitative interpretation, we deduced that the alkyl chains of CH3–10SE are almost vertically oriented at the surface and that the terminal methyl groups of the alkyl chains are tilted from the surface normal as much as θ ≈ 40?±?5°, with a broad distribution of tilt angles. We also found that rubbing treatment induced the anisotropic orientation of the alkyl side-chains perpendicular to the rubbing direction, but their orientation was unchanged by annealing. |
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| Keywords: | sum-frequency generation surface orientation alignment layer rubbing effect annealing effect |
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