Freeze resistant and flame retardant magnetoactive hydrogels with ordered particles for actuation across extreme environment

Gels are attractive candidates for intelligent actuation, but their practical use is often limited by narrow thermal operating ranges and poor stimulus responsiveness. This study presents a magnetoactive gel system with extreme-temperature resilience, achieved through the integration of antifreeze and flame-retardant components, enabling operation from −60 °C to 1000 °C. The system maintains mechanical compliance and exhibits excellent adhesion strength (475 ± 7.17 kPa). Magnetic field guided assembly of embedded microspheres creates an anisotropic filler architecture, with a saturation magnetization of 20 emu/g, enabling remote, high-fidelity actuation with sub-280 ± 6.3 ms response times. Analysis reveals that cryoprotectant and flame-retardant concentrations are key to thermal tolerance, while magnetic content and alignment govern field-driven deformation. Multiscale modeling combining molecular dynamics and finite-element analysis shows that the ordered filler network enhances load transfer and stress distribution, improving the small-strain modulus by up to 2.5 times. This work establishes a design framework for thermally resilient, magneto-responsive gels with strong adhesive properties, demonstrating that anisotropic filler alignment is critical for optimizing mechanical performance, actuation efficiency, and adhesion. The findings offer promising applications in flexible robotics, aerospace, and defense.