"Specific examples of such a substituent include, for example, functional groups such as a hydroxyl group, a halogen atom, a halogenated alkyl group, a halogenated acyl group, a halogenated allyl group, an acyl group, an allyl group, a carboxyl group, a sulfoxyl group, a phosphonium group, a ketone group, an aldehyde group, an isocyanate group, an isothiocyanate group, a carbodiimide group, a thiol" . . . . .