Huatao Wang

Highly Flexible and Sensitive Wearable E-Skin Based on Graphite Nanoplatelet and Polyurethane Nanocomposite Films in Mass Industry Production Available

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 bodys 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 volunteers 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.

Designed fabrication of hierarchical porous carbon nanotubes/graphene/carbon nanofibers composites with enhanced capacitive desalination properties

Carbonaceous materials, one of the most important electrode materials for sea water desalination, have attracted tremendous attention. Herein, we develop a facile and effective two-step strategy to fabricate hierarchical porous carbon nanotubes/graphene/carbon nanofibers (CNTs/G/CNFs) composites for capacitive desalination application. Graphite oxide (GO), Ni2+, and Co2+ are introduced into polyacrylonitrile (PAN) nanofibers by electrospinning method. During the annealing process, the PAN nanofibers are carbonized into CNFs felt, while the CNTs grow in situ on the surface of CNFs and graphite oxide are reduced into graphene simultaneously. Benefiting from the unique hierarchical porous structure, the as-prepared CNTs/G/CNFs composites have a large specific surface area of 223.9xa0m2xa0g−1 and excellent electrical conductivity. The maximum salt capacity of the composites can reach to 36.0xa0mgxa0g−1, and the adsorbing capability maintains a large retention of 96.9% after five cycles. Moreover, the effective deionization time of the CNTs/G/CNFs composites lasts more than 30xa0min, much better than the commercial carbon fibers (C-CFs) and graphene/carbon nanofibers (G/CNFs) composites. Results suggest that the designed hierarchical porous CNTs/G/CNFs architecture could enhance the capacitive desalination properties of electrode materials. And the possible adsorption mechanism of the novel electrode materials is proposed as well.

Microstructure and mechanical properties in Ni45·4Mn39·5In13·1Gd2 alloy with high transformation temperature

Abstract A Heusler Ni45·4Mn39·5In13·1Gd2 alloy with high transformation temperature has been obtained by substituting 2 at-%Gd for Mn in a ternary Ni45·4Mn41·5In13·1 ferromagnetic shape memory alloy. It is shown that the microstructure of Ni45·4Mn39·5In13·1Gd2 alloy consists of a matrix and a Gd rich phase. The Ni45·4Mn39·5In13·1Gd2 alloy exhibits a martensitic transformation start temperature of 726 K, and the transformation hysteresis is Af−Msu200a=u200a148°C. At room temperature, non-modulated martensite of tetragonal L10 structure is observed in Ni45·4Mn39·5In13·1Gd2 alloy. In addition, it is revealed that the addition of Gd significantly enhances the compressive strength and improves the ductility of Ni45·4Mn39·5In13·1Gd2 alloy.