Magnetic Field Triggered Multicycle Damage Sensing and Self Healing

Abstract

Multifunctional materials inspired by biological structures have attracted great interest, e.g. for wearable/ flexible “skin” and smart coatings. A current challenge in this area is to develop an artificial material which mimics biological skin by simultaneously displaying color change on damage as well as self healing of the damaged region. Here we report, for the first time, the development of a damage sensing and self healing magnet-polymer composite (Magpol), which actively responds to an external magnetic field. We incorporated reversible sensing using mechanochromic molecules in a shape memory thermoplastic matrix. Exposure to an alternating magnetic field (AMF) triggers shape recovery and facilitates damage repair. Magpol exhibited a linear strain response upto 150% strain and complete recovery after healing. We have demonstrated the use of this concept in a reusable biomedical device i.e., coated guidewires. Our findings offer a new synergistic method to bestow multifunctionality for applications ranging from medical device coatings to adaptive wing structures.

Bio‐Inspired Multiple Cycle Healing and Damage Sensing in Elastomer–Magnet Nanocomposites

“…NBR, NBR10, NBR20, and NBR30 samples were placed within a water‐cooled 5‐loop copper induction coil energized by an AC generator . Figure shows the plot of temperature achieved by the Magpol versus time.…”

“…Following this experiment, the ≈34% shape fixed NBR, NBR10, and NBR20 samples were individually placed within an induction coil and subjected to an AMF . As expected, the larger the MNP loading resulted in faster heating and higher maximum temperature.…”

“…NBR20 was stretched to 300% elongation. The photoluminescent emission spectra were measured during stretching at successive intervals of strain value …”

In Situ Generated Medical Devices

“…Ramanujan's earlier work demonstrated the twisting, bending, elongation, Curie temperature regulated heating, and self‐healing of MPCs, which are required for wireless and programmable in situ device fabrication of magnetic‐polymer composite medical devices (MPCMD) . In situ device fabrication and operation of MPCMD is illustrated in Figure .…”

Bioinspired Healable Mechanochromic Function from Fluorescent Polyurethane Composite Film

“…A superhydrophobic and mechanically durable biomimicking material was created by combining characteristics of the lotus leaf, mussel, and sandcastle worm . Multifunctional materials with mechanical sensing and self‐healing under magnetic fields and multistimuli were reported. The development of multifunctional materials that integrate mechanochromic and self‐healing properties is highly demanded.…”