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

Published

March 1, 2000

Author(s)

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

Abstract

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.

Citation

Macromolecules

Volume

33

Issue

No. 5

Pub Type

Journals

Keywords

polymer films, semifluorinated alkanes

Citation

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 23, 2024)