S-Space College of Engineering/Engineering Practice School (공과대학/대학원) Dept. of Chemical and Biological Engineering (화학생물공학부) Journal Papers (저널논문_화학생물공학부)
The Orientation of Semifluorinated Alkanes Attached to Polymers at the Surface of Polymer Films
- Genzer, Jan; Sivaniah, Easan; Kramer, Edward J.; Wang, Jianguo; Körner, Hilmar; Xiang, Maoliang; Char, Kookheon; Ober, Christopher K.; DeKoven, Benjamin M.; Bubeck, Robert A.; Chaudhury, Manoj K.; Sambasivan, Sharadha; Fischer, Danial A.
- Issue Date
- American Chemical Society
- Macromolecules, 2000, 33, 1882
- The surface molecular orientation of a liquid crystalline (LC) layer made up of semifluorinated (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 29−46°. 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)y− part of the molecule (y increases) at constant x.
- 0024-9297 (print)
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