Fig. 1: Design and properties of the monophasic composite muscle.

a A schematic illustration depicting the concept of the monophasic composite muscle and its multifunctionalities. b (i) Chemical composition of the composite; (ii) SEM image showing the microstructures of the composite; (iii) low- and (iv) high-resolution TEM images of the NdFeB microparticles. c (i) Working mechanism of the poly(SMA-co-EGDMA) and (ii-v) WAXS analysis images of the composites under different conditions (crystallized, amorphous, amorphous and stretched, and crystallized and stretched). d Elastic moduli and stiffness switching ratio of the composites at 25 °C and 70 °C as a function of the amount of magnetic particles. e Energy density (u) and energy efficiency (η) of the composite during the loading and unloading cycles at various strains (100–500%). f Performance benchmark between the proposed magnetic composite muscle and previous artificial muscles. Error bars in each graph represent standard deviation, n = 5 independent samples.