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4D printing is widely used in soft actuators, flexible electronic devices, and soft robotics. However, existing 4D printed architectures suffer from drawbacks such as long shape‐deformation response time or low sensitivity to external stimuli, which greatly limit their applications. To address these shortcomings, 4D printed electromagnetic architectures (EMAs) with both ultra‐fast shape‐deformation and highly‐sensitive detection capabilities have been proposed in this study. The EMA is composed of a 4D printed polymeric scaffold, along with magnetic and conductive parts. Experiments show that the EMA exhibits not only an ultra‐fast shape‐deformation response time as low as 0.007 s but also a high sensitivity to detect an external pressure down to 0.4 Pa, which is beyond records of all current 4D printing reports. Numerical simulation reveals the rapid shape‐deformation and sensing mechanism of EMAs. The effects of cell structures on the performances of EMAs are investigated by parameter optimization. Finally, a "sensing‐to‐deforming" system has been demonstrated, which can smartly distinguish objects by pressures and then trap or release them by the shape deformation. This work realized the effective coupling of ultra‐rapid shape‐deformation and ultra‐low stress sensing of 4D printed architectures and provided an effective method for integrated development of smart devices in deformation and sensing. [ABSTRACT FROM AUTHOR]

Signal transmission between rigid robots is usually realized through rigid electronic components like coil or circuit board. However, these rigid electronic units are difficult to be used in fully flexible soft robots because of the mismatch of Young's modulus. Liquid metal (LM), as a flexible fluid with superior electric conductivity, can be served as the alternative material for rigid electronic units to realize signal transmission in fully flexible soft robots. Herein, a fully flexible soft robot is fabricated, which is mainly consists of two functional units: the soft tentacle integrated with liquid metal spiral wire and the body prepared by Nd2Fe14B magnetic powders/Ecoflex composites. The fully flexible soft robot can not only transmit electric signals based on electromagnetic induction but also be actuated by an external magnetic field to form diverse signal transmission pathways. Related mechanisms of transmitting electric signal and driving are studied by Maxwell numerical simulation. Driven by an external magnetic field, three soft robots are capable to constitute two different pathways to transmit electric signals to the oscilloscope. It is believed that the integration of LM into the magnetic composites provides an open perspective to realize the signal transmission in fully flexible soft robot and favors the development of multifunctional soft robot. [ABSTRACT FROM AUTHOR]

The combination of semiconductivity and tunable ferromagnetism is pivotal for electrical control of ferromagnetism and next‐generation low‐power spintronic devices. However, Curie temperatures (TC) for most traditional intrinsic ferromagnetic semiconductors (≤200 K) and recently discovered two‐dimensional (2D) ones (<70 K) are far below room temperature. 2D van der Waals (vdW) semiconductors with intrinsic room‐temperature ferromagnetism remain elusive considering the unfavored 2D long‐range ferromagnetic order indicated by Mermin–Wagner theorem. Here, vdW semiconductor CrxGa1−xTe crystals exhibiting highly tunable above‐room‐temperature ferromagnetism with bandgap 1.62–1.66 eV are reported. The saturation magnetic moment (Msat) of CrxGa1−xTe crystals can be effectively regulated up to ≈5.4 times by tuning Cr content and ≈75.9 times by changing the thickness. vdW CrxGa1−xTe ultrathin semiconductor crystals show robust room‐temperature ferromagnetism with the 2D quantum confinement effect, enabling TC 314.9–329 K for nanosheets, record‐high for intrinsic vdW 2D ferromagnetic semiconductors. This work opens an avenue to room‐temperature 2D vdW ferromagnetic semiconductor for 2D electronic and spintronic devices. [ABSTRACT FROM AUTHOR]

Thrombosis is a significant threat to human health. However, the existing clinical treatment methods have limitations. Magnetic soft matter is used in the biomedical field for years, and ferromagnetic liquids exhibit tunable stiffness and on-demand movement advantages under magnetic fields. In this study, a ferromagnetic liquid robot (FMLR) is developed and applied it to thrombus removal in complex blood vessels. The FMLR consisted of Fe 3 O 4 magnetic nanoparticles and dimethyl silicone oil. The FMLR can pass through a narrow complex maze through shape deformation by tailoring the intensity and direction of the external magnetic field. Finite element simulation analysis is used to validate the mechanism of controllable FMLR movements. Importantly, the storage modulus of FMLR can be tuned from 0.1 to 2018 Pa by varying the external magnetic intensity, ensuring its effectiveness in removing rigid and stubborn thrombi present on the vascular walls. Toward medical robotic applications, FMLR can be used in telerobotic neurointerventional. Experiments demonstrating the capability of FMLR to remove thrombi in the ear veins of rabbits are conducted. This study introduces an efficient approach for thrombus elimination, broadening the utilization of FMLRs within the realm of clinical medicine., (© 2024 Wiley‐VCH GmbH.)

The change of 3D spatial distribution of magnetic permeability can lead to the generation of introduced electrical signals. However, present studies can only achieve rough regulation by simple shape deformation of magnetic elastomers such as compression, bending, or stretching. Accurate control of the 3D spatial distribution of magnetic permeability is still an open question. In this study, an on-demand 3D spatial distribution of magnetic permeability by controlled flowing of Fe 3 O 4 nanoparticle liquid (FNL) is demonstrated. The flowing routes of FNL are tuned by a 3D-printed cage with pre-designed hollow structure, thus changing the 3D spatial distribution of magnetic permeability. Then, eight symmetrically distributed coils under cage are used to receive characteristic induction voltage signals. Maxwell numerical simulation reveals the working mechanism of signal generation. Notably, those eight coils can detect FNL flowing status in eight directions, allowing recognition of up to 255 different FNL flowing combinations. By introducing machine learning, the micro-cavity detector based on FNL can distinguish nine kinds of micro-cavity structures with an accuracy of 98.77%. This work provides a new strategy for the adjustment of the 3D spatial distribution of the magnetic permeability and expands the application of FNL in the field of space exploration., (© 2023 Wiley-VCH GmbH.)

The combination of semiconductivity and tunable ferromagnetism is pivotal for electrical control of ferromagnetism and next-generation low-power spintronic devices. However, Curie temperatures (T C ) for most traditional intrinsic ferromagnetic semiconductors (≤200 K) and recently discovered two-dimensional (2D) ones (<70 K) are far below room temperature. 2D van der Waals (vdW) semiconductors with intrinsic room-temperature ferromagnetism remain elusive considering the unfavored 2D long-range ferromagnetic order indicated by Mermin-Wagner theorem. Here, vdW semiconductor Cr x Ga 1- x Te crystals exhibiting highly tunable above-room-temperature ferromagnetism with bandgap 1.62-1.66 eV are reported. The saturation magnetic moment (M sat ) of Cr x Ga 1- x Te crystals can be effectively regulated up to ≈5.4 times by tuning Cr content and ≈75.9 times by changing the thickness. vdW Cr x Ga 1- x Te ultrathin semiconductor crystals show robust room-temperature ferromagnetism with the 2D quantum confinement effect, enabling T C 314.9-329 K for nanosheets, record-high for intrinsic vdW 2D ferromagnetic semiconductors. This work opens an avenue to room-temperature 2D vdW ferromagnetic semiconductor for 2D electronic and spintronic devices., (© 2021 The Authors. Advanced Science published by Wiley-VCH GmbH.)