A polymer is described herein that includes a plurality of N-J-N or N—C—S repeating units, wherein each J is independently a carbon atom, an alkyl group, or an aryl group; a plurality of hydrophilic groups bonded with the repeating units; and a plurality of hydrophobic groups bonded with the hydrophilic groups and the repeating units. Such polymers may be made into hydrogels by exposure to water, and the hydrogels may be used as delivery vehicles for various payloads.