Swelling, states of water, morphology, stability in the aqueous solution, and electro-mechano-chemical bending behaviors of the gelatin–chitosan blend system were studied in order to clarify the potential use of this blend system as an actuator. The gelatin–chitosan blend system was prepared in order to avoid dissolution of the pure chitosan in an aqueous medium and the rigidity and easy degradation of the pure gelatin in the swollen state.

We prepared multi-walled carbon nanotube (MWNT)/gelatin composites by dispersion of MWNT through ultrasonication in an aqueous medium with anionic surfactant sodium dodecyl sulfate (SDS). The swelling behavior and the bending mechanism of the composite and pure gelatin films were studied in order to clarify the potential use of MWNT in the gelatin actuator. The response of the composite and pure hydrogel to the applied electrical field in the NaCl aqueous solution was investigated.