A copolymer comprising a repeat unit A, wherein repeat unit A comprises a repeat unit B, wherein repeat unit B comprises and at least one optional repeat unit D, wherein repeat unit D comprises an aryl group. In this copolymer, X1, X2, X3, and X4 are independently selected from the group consisting of: H, Cl, F, CN, alkyl, alkoxy, ester, ketone, amide and aryl groups and R1, R2, R3, R4, R5 and R6 are independently selected from the group consisting of: H, Cl, F, CN, alkyl, alkoxy, alkylthio, ester, ketone and aryl groups.