Smart materials, particularly thermoresponsive hydrogels, have gained significant attention in fields like soft robotics due to their ability to respond to external stimuli such as temperature. This study focuses on the synthesis and characterization of Poly(N-isopropylacrylamide) (PNIPAM) hydrogels, exploring how varying concentrations of monomers and crosslinkers influence their mechanical properties, swelling behaviour, and fatigue resistance. Using a combination of experimental methods, including rheometry, indentation tests, swelling-deswelling analyses, and cyclic loading-unloading (fatigue) tests, alongside Finite Element Method (FEM) simulations, this research examines the relationships between these concentrations and hydrogel properties. Results indicate that the mechanical stiffness, swelling ratios, and fatigue resistance can be modulated by adjusting the concentrations of monomer and crosslinker, making PNIPAM hydrogels a promising material for applications requiring tuneable mechanical properties and durability. This study contributes to the advancement of soft robotics by providing insights into the material properties and behaviours needed for practical applications and by suggesting avenues for future research in hydrogel-based actuation systems.

mart materials are already often used as actuator or sensors, as well in soft grippers as other fields. However, the application of thermoresponsive smart materials as actuator is still a potential field. As electroactive polymers and shape memory alloys are commonly used thermoresponsive smart materials for actuators in soft grippers, a novel design will contribute to this area by adding a new potential field: soft grippers actuated by thermoresponsive hydrogel particles. A structure, filled with thermoresponsive hydrogel particles which will swell after decreasing the temperature, will act as a gripper. After considering the relevant
parameters of soft grippers for this research, multiple demo structures are manufactured and compared with simulations. Additionally, the effect of these parameters on the bending performance is determined with
a Design of Experiments. At last, a potential configuration of a multi segmented adaptive soft grippers is presented.