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The Orientation of Semifluorinated Alkanes Attached to Polymers at the Surface of Polymer Films



Jan Genzer, E Sivaniah, E K. Kramer, J G. Wang, H Kerner, M Xiang, K Char, Christopher K. Ober, B M. DeKoven, Robert A. Bubeck, M K. Chaudhury, S Sambasivan, Daniel A. Fischer


The surface molecular orientation of a liquid crystalline (LC) layer made up a semi-fluorinated (SF) single side-groups [-CO-(CH2)x-1-(CF2)yF] (single SF groups) attached to polyisoprene homopolymer or the isoprene block of a styrene-isoprene diblock copolymer was determined by analyzing the partial electron yield C-edge NEXAFS signal. The results show that the surfaces of thin SF polymer films are covered with a uniform layer, consisting of the SF-LC groups whose average -CF2- tilt angle with the surface normal lies in the range 29 to 46 . This is in direct contrast to the bulk, where the directors of the SF-LC mesogens are aligned parallel to the polystyrene/SF-polyisoprene interface of the block copolymers. This average tilt angle increases with increasing the length of the -(CH2)x-1- group (x increases) but decreases with increasing the length of the -(CF2)1- part of the molecule (y increases) at constant x.
No. 5


polymer films, semifluorinated alkanes


Genzer, J. , Sivaniah, E. , Kramer, E. , Wang, J. , Kerner, H. , Xiang, M. , Char, K. , Ober, C. , DeKoven, B. , Bubeck, R. , Chaudhury, M. , Sambasivan, S. and Fischer, D. (2000), The Orientation of Semifluorinated Alkanes Attached to Polymers at the Surface of Polymer Films, Macromolecules (Accessed April 17, 2024)
Created February 29, 2000, Updated October 12, 2021