Patent ID: 8044217

Claim:
A monomer of the formula (XI) wherein Y is identical or different on each occurrence and is in each case S or O; Ar is identical or different on each occurrence and is in each case phenylene and may be unsubstituted or substituted by fluorine or by one or more radicals R, OR or NR 2 ; R is identical or different on each occurrence and is in each case H, a linear, branched or cyclic alkyl chain which has from 1 to 22 carbon atoms and in which one or more nonadjacent carbon atoms is optionally replaced by O, S, —CO—O— or —O—CO—O—, where one or more H atoms may also be replaced by fluorine, or a substituted or unsubstituted aryl group which has from 5 to 40 carbon atoms and in which one or more carbon atoms is optionally replaced by O, S or N, and the broken-line bonds indicate the linkage in the polymer.