To prepare chitosan (CS) hydrogels with high mechanical properties, chitosan-carbon nanotube (CNT-CS) composites were added into CS hydrogels. A series of CS-CNT/CS semi-IPN (interpenetrating) hydrogels were prepared by a pre-freezing and sequentially freeze-drying technique using glutaraldehyde as a crosslinker. The mechanical properties of all hydrogels were tested. In the buffer solutions with different pH values, the deswelling and swelling behavior of CS-CNT/CS semi-IPN was studied. In contrast with the normal CS hydrogel, the mechanical strength of these semi-IPN hydrogels was remarkably improved, while the pH sensitivities were well preserved.

Key words: carbon nanotube, nanocomposite, pH sensitivity, mechanical property