Improving Electro-Mechano-Chemical Performance of Alginate Hydrogel Artificial Muscles Through Micro-Nano Doping

Alginate hydrogel artificial muscles (AHAMs) are promising electrically responsive chemical actuators using ion migration, ideal for flexible and biological applications. However, they face challenges such as low response actuation and short operating life. This study explored doping alginate hydrogels with micro-nanomaterials to improve their electro-mechano-chemical performance. Carboxylated multi-walled carbon nanotubes are covalently bonded to sodium alginate (SA) through esterification, enhancing electrical conductivity and response actuation. Graphene oxide formed a compact structure via carboxyl and hydroxyl interactions, dispersing SA molecules, reducing agglomeration, and enhancing ion channel stability, which reduced resistance by 36.8%. Meanwhile, the sulfonic acid group in polystyrene sulfonate sodium improved water retention and lowered the elastic modulus. Crosslinking with SA created a stable hydrogel network, boosting anion concentration and aiding hydrated cation migration. This led to a 52.3% decrease in the elastic modulus of AHAM, resulting in a maximum actuated force-mass ratio up to 5.9 times higher than the control group.