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Graphene and nanomaterials based flexible pressure sensors R&D activities are becoming hot topics due to the huge marketing demand on wearable devices and electronic skin (E-Skin) to monitor the human body's actions for dedicated healthcare. Herein, we report a facile and efficient fabrication strategy to construct a new type of highly flexible and sensitive wearable E-Skin based on graphite nanoplates (GNP) and polyurethane (PU) nanocomposite films. The developed GNP/PU E-Skin sensors are highly flexible with good electrical conductivity due to their unique binary microstructures with synergistic interfacial characteristics, which are sensitive to both static and dynamic pressure variation, and can even accurately and quickly detect the pressure as low as 0.005 N/50 Pa and momentum as low as 1.9 mN·s with a gauge factor of 0.9 at the strain variation of up to 30%. Importantly, our GNP/PU E-Skin is also highly sensitive to finger bending and stretching with a linear correlation between the relative resistance change and the corresponding bending angles or elongation percentage. In addition, our E-Skin shows excellent sensitivity to voice vibration when exposed to a volunteer's voice vibration testing. Notably, the entire E-Skin fabrication process is scalable, low cost, and industrially available. Our complementary experiments with comprehensive results demonstrate that the developed GNP/PU E-Skin is impressively promising for practical healthcare applications in wearable devices, and enables us to monitor the real-world force signals in real-time and in-situ mode from pressing, hitting, bending, stretching, and voice vibration.

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High-performance electromagnetic (EM) wave absorbing materials are strongly desired in many fields like portable devices and aircraft. Introducing carbon nanotubes (CNTs) to certain materials has been proved to be an effective method leading to good EM wave absorption capability. In this work, CNTs are successfully synthesized on SiC fibers with high speed by using a newly developed method which is far more efficient than the commonly used one. The obtained CNT/SiCf composites exhibit high-performance EM wave absorption capability. With 0.72 wt % CNTs, the reflection loss of the 4 mm composite with only 20 wt % filler loading reaches −62.5 dB with the broad effective absorption bandwidth of 8.8 GHz, covering almost the entire Ku band and three-quarters X band. Moreover, the composites can be added to varying matrices so as to modify their EM wave absorption and other properties. The EM wave absorption performance can be easily tuned in a wide range by varying the CNT content, thickness, and filler loading. This work offers a new route for efficiently synthesizing CNTs but, more importantly, for designing high-performance and multifunctional EM wave absorbing materials.

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The amplified spontaneous emission and gain characteristics of various fluorescent dyes, 2-(1,1-dimethylethyl)-6(2-(2,3,6,7-tetrahydro-1,1,7,7-tetramethyl-1H,5H-benzo[ij] quinolizin-9-1)ethenyl)-4H-pyran-4-ylidene) propanedinitrile (DCJTB) and 4-dicyanomethylene-2-methyl-6-(p-dimethyl-aminostyryl)-4H-pyran (DCM), doped in polystyrene (PS) matrices were studied and compared. It was found that DCJTB has a larger net gain, 40.72 cm(-1), a lower loss, 2.49 cm(-1), and a lower threshold, 0.16 (mJ/ pulse)/cm2, than DCM, which has a net gain of 11.95 cm(-1), a loss of 9.25 cm(-1), and a threshold of 4(mJ/pulse)/cm2. The improvement of performance in DCJTB PS films is attributed to the larger free volume of DCJTB caused by the introduction of steric spacer groups into the DCJTB molecule.