The Chinese University of Hong Kong (CUHK)’s Department of Mechanical and Automation Engineering led a collaborative team of researchers in the development of a ferromagnetic silicone elastomer with three-dimensional (3D) deformability.
The technology is expected to expand the application potential of morphable soft materials across engineering fields, such as shaping more flexible soft robots. The research results have been published in Nature Communications.
Current limitations of deformation freedom surpassed via tech
Flexible electronic devices and smart systems, including micro-antennas, smart adhesive devices and wireless near-field communication devices, commonly use soft materials owing to their ability to bend and deform. Currently, the general quasi-static control strategies for controlling the deformation of soft materials can only switch between two forms of morphological configurations including initial and deformed morphologies. They are unable to achieve a higher degree of freedom and more complex multi-form dynamic control, meaning the corresponding functionalities are limited.
Professor Zhang Li and Dr Jin Dongdong from CUHK Department of Mechanical and Automation Engineering, together with Professor Zhang Jiachen from the City University of Hong Kong and Professor Wang Liu from the University of Science and Technology of China, have developed a magnetic dynamic regulation strategy that addresses the limitations of the existing quasi-static regulation via the use of a magnetic field to control the transformation of soft materials.
They developed a swellable magnetic elastomer that was affixed to a hard glass substrate. This was then immersed in toluene, an organic solvent. Once the toluene was absorbed by the elastomer, it diffuses and causes swelling. Under the constraint of the substrate, the elastomeric structure undergoes a buckling transformation to form a 3D wave-like structure.
To magnetise the elastomers during the swelling process, a strong pulse magnetic field, produced by a magnetiser, is applied. Then, the undeformed state that sets the 3D anisotropic magnetisation profiles in the elastomeric structures is recovered.
Programmed magnetic inputs including strengths, directions and gradients facilitate the realisation of multimodal dynamic regulation of morphable structures such as travelling wave-form transformations which are well beyond their quasi-static states.
Credits: CUHK, Press Release
Fish fins inspire new technology
Professor Zhang Li stated that natural organisms often exhibit highly controllable morphological transformations that enable their adaptability to the physical environment. For example, the knifefish ensures its locomotion is manoeuvrable and stable by regulating its wavy ribbon fins.
The team was inspired by knifefish fins which buckle freely; they developed a magnetic elastomer that can freely deform to achieve the multimodal transformation of 3D structures at different dimensional scales.
By modulating the driving magnetic field, the dynamic geometric reconfiguration of the magnetic elastomer is achieved to exhibit a series of switchable fluid properties such as directional flow, mixing and vortex, and showcases its potential applications in fluidic manipulation, selective object trapping, sensitivity-enhanced biomedical analysis, soft robotics and other fields.
Looking ahead, the team will further apply magnetic elastomers to their research on micro-robots and explore related biomedical applications.
The project has been supported by the Research Grants Council (RGC), the HKSAR Innovation and Technology Commission (ITC), the Croucher Foundation, the CUHK T Stone Robotics Institute, the SIAT-CUHK Joint Laboratory of Robotics and Intelligent Systems, and the Multi-Scale Medical Robotics Center (MRC), InnoHK, at the Hong Kong Science Park.
