Self-Healing of Core–Shell Magnetic Polystyrene Nanocomposites

Abstract

High heat generation is reported in core-shell magnetic nanoparticle polystyrene (PS) nanocomposites (3.5, 10 wt %) when they are placed in a high-frequency ac magnetic field. These magnetic nanoparticles with cobalt iron oxide core and manganese iron oxide shell were synthesized and characterized by wide-angle X-ray scattering (WAX), thermal gravimetric analysis (TGA), transmission electron microscopy (TEM), and ac field gradient magnetometery. When placed in a high-frequency ac magnetic field, the thermal energy generated in the magnetic polystyrene nanocomposites resulted in a surface temperature increase. The heat generation is attributed to the contribution of Néel relaxation and hysteresis of the core-shell magnetic nanoparticles in the solid state. The maximum surface temperature increased with increasing nanoparticle content and resulted in melting of the magnetic polystyrene nanocomposite.

Induction heating induced self-healing of nanocomposites based on surface-functionalized cationic iron oxide particles and polyelectrolytes

“…[34] Since then the approach was carried over to other polymer systems, including styrene, ethylene-vinyl acetate and propylene-ethylene-1-butene. [35][36][37] Hohlbein et al have also shown that the heat generated in the alternating magnetic field accelerates supramolecular healing mechanisms, in this case purchased from Alfa Aesar. Sodium bicarbonate (> 99%) was purchased from Fluka.…”

Challenges and Opportunities of Self‐Healing Polymers and Devices for Extreme and Hostile Environments

“…Under the influence of a high magnetic field, the magnetically responsive fillers vibrate and agitate, increasing the temperature inside the polymer matrix, also referred to as Néel relaxation. [ 124 ] Depending on the nature of the polymer, this can lead to one of two responses. First, the increased temperature of the polymer can lead to surface rearrangement, surface approach, and then wetting followed by chain diffusion and randomization as time progresses during the self‐healing process.…”

“…This initiated polymer melt flow into the microcrack, resulting in a visually observed self‐healing effect. [ 124 ]…”

Self‐Healing of Electrical Damage in Polymers

“…With these three requirements matched, the particles were observed to automatically migrate toward the surface of electrical tree channels, generating localized high temperature, and to re-disperse after remolding the damaged regions ( Figure 5). [61] Different from previous self-healing research using superparamagnetic nanoparticles in which the edges of separated parts have to be put in good contact before healing, [136][137][138] the emerging approach with defect-targeted migration of the nanoparticles can repeatedly heal hollow tree channels and restore insulating properties. Interestingly, only less than 0.1 vol% of the superparamagnetic nanoparticles was found to be sufficient for the healing, which was attributed to the automatic and targeted transport and assembly of the nanoparticles toward the defect site.…”