Antioxidant ability and increased mechanical stability of hydrogel nanocomposites based on N-isopropylacrylamide crosslinked with Laponite and modified with polydopamine

A new nanocomposite hydrogel with antioxidant activity was obtained. In the synthesis, first, the free-radical polymerization of NIPA (N-isopropylacrylamide) with Laponite as the crosslinker was performed, and then the hydrogel was further modified with polydopamine to yield a mechanically improved antioxidant hydrogel. ABTS (2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt) assays were used to examine the antioxidant activity of the obtained material, the material reached ca. 98 % of inhibition after 30 min. The new NIPA-based hydrogel was temperature responsive; as a result, the nanocomposite double network hydrogel exhibited temperature-modulated antioxidant activity. The mechanical properties of the obtained composite were examined using a tensile machine; the tensile strength of PNIPA_6%Lap/ PDA hydrogel reached 20 kPa, and elongation at break equaled 250 %.