Iota-carrageenan (𝑖C) hydrogel oscillations under constant electric field and stability diagrams

Soft actuators belong to a type of actuators made of soft materials which are capable of converting applied energy to mechanical motion. They have been utilized in several fields due to their flexibility, low weight, inexpensiveness and simple fabrication. In this work, iota-carrageenan (𝑖C) was chosen as the starting material for a hydrogel-based actuator. The 𝑖C hydrogels were fabricated via a simple solvent-casting technique at various concentrations: 2.4% (v/v), 2.8% (v/v) and 3.2% (v/v). All 𝑖C hydrogels were characterized for their chemical, thermal, rheological and morphological properties as well as the actuation performances under applied electric field. The 𝑖C hydrogels showed monotonic increases in the static bending distance and dielectrophoretic force with increasing electric field strength. Above the critical electrical field strengths, the ribbon-like 𝑖C hydrogels oscillated back and forth due to the competition between the dielectrophoresis force, the resisting elastic force, the weight and the inertia force. Stability diagrams were constructed for the first time separating static bending from oscillation behavior under constant applied electric fields. © 2024 Society of Chemical Industry.