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Polymer-based positive temperature coefficient (PTC) composites are of special interest because they have great potential in temperature-sensitive devices. In this work, composites based on polypropylene and carbon black (CB) particles were prepared by solution blending. The electrical and mechanical properties of composites were measured when CB particles were treated with silane coupling agent before added to the PP matrix. It was found that CB treated by coupling agent exhibited a higher filler-polymer interaction which was reflected in the improvement of the mechanical properties and the modification of electrical conductivity of composites, especially when measured against the temperature. The effect of heat treatment on the electrical conductivity, PTC behavior and mechanical properties was also studied. It turned out that the optimal heat treatment condition of composites was at 120°C for 3 h. The differential scanning calorimetry analysis and X-ray diffraction analysis revealed that heat treatment could increase the crystallinity of composites, so that the PTC intensity increased.

For many applications of dielectric elastomer (DE) actuators, it is desirable to endow the DE with a high dielectric constant (e), high breakdown field, and good flexibility. In this study, a high-e nanocomposite acrylic elastomer (ACM)-g-copper phthalocyanine (CuPc) was fabricated, in which the CuPc oligomer was grafted onto the backbone of ACM. This grafted composite exhibited several benefits over the physically blended one. Transmission electron microscopy micrographs indicated that the size of the grafted CuPc was in the range 15-30 nm, which was more than 25 times smaller than that of the simply blended one. At room temperature, e of ACM-g-CuPc (with 15 wt % CuPc) reached 303 at 100 Hz. The remarkable enhancement in the dielectric response could be attributed to the greatly strengthened exchange coupling effect and the Maxwell-Wagner-Sillars polarization mechanism.

Transient global amnesia (TGA) is a benign memory disorder with etiologies that have been debated for a long time. The prevalence of stressful events before a TGA attack makes it hard to overlook these precipitating factors, given that stress has the potential to organically effect the brain. Cortical spreading depression (CSD) was proposed as a possible cause decades ago. Being a regional phenomenon, CSD seems to affect every aspect of the micro-mechanism in maintaining the homeostasis of the central nervous system (CNS). Corresponding evidence regarding hemodynamic and morphological changes from TGA and CSD have been accumulated separately, but the resemblance between the two has not been systematically explored so far, which is surprising especially considering that CSD had been confirmed to cause secondary damage in the human brain. Thus, by deeply delving into the anatomic and electrophysiological properties of the CNS, the CSD-TGA model may render insights into the basic pathophysiology behind the façade of the enigmatic clinical presentation.