Polymeric material comprising ortho-positioned acidic groups
The present invention relates to a polymeric material comprising structural elements of the following general formula (I): wherein Ph1, Ph2 and Ph3 independently are phenylenes comprising acidic groups with or without a spacer or salts thereof; X1, X2, X3 and X4 independently are O, S, SO, SO2, or a direct bond and wherein X1 also may be H termination when Formula (I) relates to side chains of the
