Biodegradable, Sustainable Hydrogel Actuators with Shape and Stiffness Morphing Capabilities via Embedded 3D Printing

Abstract Despite the impressive performance of recent marine robots, many their components are non‐biodegradable or even toxic and may negatively impact sensitive ecosystems. To overcome these limitations, biologically‐sourced hydrogels a candidate material for robotics. Recent advances in embedded 3D printing have expanded design freedom hydrogel additive manufacturing. However, small‐scale hydrogel‐based actuators remains challenging. In this study, Free form reversible embedding suspended (FRESH) is applied to fabricate biologically‐derived, marine‐sourced hydraulic by thin‐wall structures that water‐tight pressurizable. Calcium‐alginate used, sustainable biomaterial sourced from brown seaweed. This process allows complex shapes internal cavities difficult achieve with traditional fabrication techniques. Furthermore, it demonstrates fabricated biodegradable, safely edible, digestible organisms. Finally, chelation‐crosslinking mechanism implemented dynamically modify alginate actuators' structural stiffness morphology. study expands possible space biodegradable robots improving manufacturability soft devices using materials.