are a hydrogen atom, a hydroxyl group, a substituted or unsubstituted alkyl, aryl, alkyloxy, or aryloxy group; and each of m, n and o are independently the same as or different from each other and are each an integer from about 0 to about 8. [0130] In one particular embodiment of formula 13, each of X and Y is a hydroxyl group and each of R1 and R2 is a methyl group.