Magnetostrictive and Electroconductive Stress‐Sensitive Functional Spider Silk

Abstract

Electronics and soft robotics demand the development of a new generation of hybrid materials featuring novel properties. Among these, remarkable mechani cal properties are required to sustain mechanical stresses, and electrical and magnetic properties are essential to design the devices' interface. In this study, a hybrid material is presented, consisting of a spider silk thread, providing mechanical robustness, coated with a layer of a magnetostrictive FeCo alloy, which ensures both electrical conductivity and stress-sensitive magnetic properties. The durability and the homogeneity of the composite are validated, as well as its ability to respond to magnetic and mechanical stimuli. Despite the coating, the soft nature of the silk and its mechanical performances are preserved. The magnetic study reveals that the magnetic behavior of the film is strongly affected by the silk thread-FeCo layer interaction, especially under mechanical stresses. Indeed, when the composite is subjected to tensile strain, the magnetic signal changes accordingly, indicating that the layer-silk interaction is maintained and can be exploited to reveal the tensional state of the sample even under severe cycles. Therefore, the presented hybrid material is a flexible fiber with properties that are suitable for magneto-electronics applications, e.g., magnetic actuators as well as strain/stress sensors.

Bioinspired acoustic metamaterials: From natural designs to optimized structures

“…The diversity in the composition of the different types of silk used by the spiders to build webs also allows a wide range of mechanical properties (Arakawa et al, 2022). Their resulting versatility has led to the emergence of many spider web-based applications in the past years, such as stresssensitive silk for soft robotics (Spizzo et al, 2022) and hybrid biomaterials for bone tissue engineering applications (Dellaquila et al, 2020). Spider dragline silk has also been shown to possess an indirect hypersonic phononic band gap and a negative group velocity region (Schneider et al, 2016), thus suggesting that this type of material can also be used as a means to control the flow of phonons, serving as tunable heat management devices (Su and Buehler, 2016).…”

Research Progress on Spider‐Inspired Tough Fibers†

“…Spizzo et al . [ 121 ] coated the spider silk from Cupiennius salei with FeCo alloy using a high‐vacuum DC magnetron sputtering device (Figure 15 a—c). Although the mechanical properties were lower than those of natural spider silk, the system could maintain good electrical conductivity under strain conditions.…”

Effect of High-Anisotropic Co2+ Substitution for Ni2+ on the Structural, Magnetic, and Magnetostrictive Properties of NiFe2O4: Implications for Sensor Applications

“…Magnetostriction, in which the physical dimensions of magnetic materials change when a magnetic field is applied, is of great relevance for the development of cutting-edge sensors for automotive and energy technology. − Magnetostriction often involves a reversible energy exchange between the mechanical form and the magnetic form. In reality, magnetostrictive materials can be used in numerous industrial applications, particularly in sensors and actuators, because of their capacity to convert a precise amount of energy from one form to another. − As a result, currently, there is an enormous interest in one particular group or family of functional materials that exhibit magnetostriction and are called magnetostrictive smart materials (MSMs). ,,,− Due to their magnetoelastic properties, these MSMs are also widely used in a variety of technological applications, such as stress sensors, actuators, magnetostrictive filters, controlled fuel injection systems, sensors, sonar transducer systems, etc. Alloy-based MSMs, such as Terfenol-D and Galfenol, exhibit exceptional magnetostriction strain (λ) but only in the single-crystal form.…”