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 polyisoprenehomopolymer or the isoprene block of a styrene−isoprene diblock copolymer was determined by analyzingthe partial electron yield C-edge NEXAFS signal. The results show that the surfaces of thin SF polymerfilms are covered with a uniform layer, consisting of the SF−LC groups whose average −CF2− tilt anglewith the surface normal lies in the range 29−46°. This is in direct contrast to the bulk, where the directorsof the SF−LC mesogens are aligned parallel to the polystyrene/SF−polyisoprene interface of the blockcopolymers. This average tilt angle increases with increasing the length of the −(CH2)x-1− group (xincreases) but decreases with increasing the length of the −(CF2)y− part of the molecule (y increases) atconstant x.
