A compound having the formula below. X is hydroxyl, a sulfonic ester or salt thereof, a phosphonate or salt thereof, a carboxylate or salt thereof, or a boronic ester or salt thereof. The value n is an integer greater than or equal to 2. A polymer made by polymerizing the compound. A method of: reacting NH2—(CH2—CH2—O)n—CH2—CH2—OH with thiophene acid chloride to form a (SC4H3)—CO—NH—(CH2—CH2—O)n—CH2—CH2—OH amide; reacting the amide with a vinyl sulfonic ester, a vinyl phosphonate, a vinyl carboxylate, or a vinyl boronic ester to form an intermediate; and converting the intermediate to a salt form.