Synthesis and characterization of gelatin-based hybrid magnetic hydrogels

Gelatin-based magnetic hydrogels are composed of gelatin polymer, water, and magnetic nanoparticles. The properties of embedded nano-particles, such as coercivity and remanent magnetization, play an essential role while designing hydrogels for specific applications such as soft robotic tentacles, which can be used in minimally invasive surgery (e.g., catheters and endoscopes). The effective properties of the magnetic hydrogels can be tuned by combining various soft and hard magnetic nanoparticles. In the present work, carbonyl iron and strontium hexaferrite are used to prepare the hybrid hydrogels. The magnetization response (m-h curve) of the hydrogels is experimentally obtained, and the results confirm that the hydrogels’ effective properties are dependent on the embedded particles. Furthermore, experimental compression tests confirm that the stiffness of the hybrid hydrogels (75 kPa) is higher than the pure hydrogels (16.5 kPa). Subsequently, the strain developed in the hydrogels under the magnetic field is measured using the digital image correlation (DIC) method. Thus, the present study provides useful insights into synthesizing soft and hard magnetic hydrogels with customized magnetic and mechanical properties.