Development and analysis of a 3D printed hydrogel soft actuator

Polyelectrolyte hydrogels produce mechanical motion in response to electrical stimulus making them a good candidate for implementation of soft actuators. However, their customary fabrication process has thus far hindered their applicability in a broad range of controlled folding behaviours. This paper employs the 3D printing technology does the development of polyelectrolyte hydrogel soft actuators. A 3D printed soft hydrogel actuator with contactless electrodes is presented for the first time. Initially chitosan as a candidate of polyelectrolytes which possess both printability and stimuli responsive is opted for ink preparation of 3D printing. The printing parameters are optimised for fabrication of desired geometrical model and the printing effects on actuation performance is analysed. It is demonstrated that increasing the surface to volume ration increase made by 3D printing improves the functionality of the actuation in the form of higher deflection rate and scale compared to a cast film hydrogel actuator. The 3D printed actuator has more potential applications because of possibilities of introducing custom geometrical, functional, and controllable properties compared to conventional cast.