Fig. 3: Self-divisions of untethered ETACs (electromagnetically transitional and actuatable material-based continuums).

a Illustration of the self-division working principle. An entire ETAC with a predefined magnetization profile can be divided into several sub-continuums while maintaining their magnetization profiles. Considering the practical implementation in biomedical scenarios, customized induction coils can be applied to conduct different surgical tasks. b Infrared images showing the ETAMs’ (electromagnetically transitional and actuatable material-based materials) thermodynamic performance under the RF heating for self-divisions. The number on the top-left side denotes the applied material type: nanoparticle (NP) type-NP weight fractions (%)-distance to the coil (mm)-induction coil types. The NP weight fraction is calculated as the ratio of NP mass to PCL (Polycaprolactone) mass. C1 and C2 in the figure legend refer to the solenoid and disk-shaped coils, respectively. c Time-dependent temperature changes during RF heating with respect to material types, distances to coils, and coil types. Cases without showing NP weight fractions, coil types, and heating distances are regarded as default values of 80%, C1, and 8 mm, respectively. d Infrared and real-time images of ETACs’ thermodynamic performances under the RF heating generated by a solenoid induction coil. Numbers of “i”-“iv” denote the heating priority. e Self-division strategies. (i) An entire ETAC can respond to external magnetic fields performing bending motions. The division region is preset at the F-region in the middle of the continuum. (ii) Pulling division strategy. (iii) Twisting division strategy. (iv) Bending division strategy. Scale bar: 1 cm. f Relations between the heating temperature and maintained magnetization profiles. Results show that divisions in the softening state have no obvious negative effect on maintaining magnetization profiles. g An ETAMs-branch system withers its branches by different self-division strategies. Scale bar: 1 cm. Source data are provided as a Source Data file.