Wearable heaters have been increasingly attracting researchers' great interest due to their efficient utility in maintaining warmth and in thermotherapy. Nowadays carbon nanomaterials and metallic nanowires tend to become the mainstream heating elements in wearable heaters considering their excellent electrical and mechanical properties. Though considerable progress has been made, there still exist challenging issues that need to be addressed in practical applications, including bad breathability and poor endurance to mechanical deformations. Here, we devise a copper nanowire based composite fiber with a unique hierarchical structure. This fiber possesses not only excellent heating performance, but also fantastic tolerance to mechanical impact, such as bending, twisting, and stretching. We further weave these fibers into a wearable heating fabric and realize smart personal heating management through an Android phone by integrating with a microcontroller unit. Two practical applications are demonstrated including a heating kneepad for articular thermotherapy and a heating coat on an infant model for maintaining warmth.
possess high electric conductivity, improved chemical & physical stability, and ultrahigh mass transfer efficiency. Therefore, in the past several decades, 1D carbon nanostructures have been exploited as robust materials in catalysis, [2] either as active materials or functional matrices to anchor various metal species. [3] To improve the application potential, introduction of heteroatoms into the 1D carbon nanostructure is essential as it allows to effectively engineer the electronic structure. [4] P and N are the popular choices but incorporating these heteroatoms into 1D carbon nanostructures normally needs multiple synthetic steps. It is important to develop simple and controllable method to synthesize heteroatom-doped 1D carbon nanostructures with superior abilities in cutting-edge applications.Alkene hydrosilylation is the addition of SiH to the unsaturated bonds, which is one of the most important chemical reactions to produce the organosilicon compounds. Platinum (Pt) homogeneous catalysts, namely the Speier Pt catalyst and Karstedt Pt catalyst, [5] have been the most popular choice in alkene hydrosilylation [6] and consume nearly 5.6 tons of platinum annually in silicone industry. [7] Unfortunately, the side reactions, including the alkene isomerization and dehydrogenative silylation, normally accompany with the main reaction, and expensive purification is needed. [8] Moreover, the additional side reactions occur due to the formation of colloidal Pt species, [9] and the recycling of Pt homogeneous catalyst is a wellknown challenge. This not only increases the production cost but also introduces impurities to the final product. [10] In this context, single-atom catalysts, which contains atomic dispersion of active metallic species on a support, have been recently developed to overcome these challenges. It exhibits an unexpected catalytic performance, while it also owns great convenience in recovery. The synthesis of the atom support is the key step to obtain this interesting material.More recently, based on P 2 O 5 chemistry, we successfully synthesized metal-free COP functionalized carbon-nanofiber assemblies. [11] This unique carbon nanostructure was proven to possess exceptional adsorption properties, a useful pre-requirement for catalysis. The outcome further inspired us to upgrade this in situ P 2 O 5 chemistry to introduce novel functional groups to 1D carbon nanostructure. Unfortunately, the previously Single-atom catalysts have become a popular choice in various catalysis applications, as they take advantages of both homogeneous catalysis (e.g., high efficiency) and heterogeneous catalysis (e.g., easy catalyst recovery). The atom support plays an indispensable role in anchoring atomic species and interplaying with them for ultimate catalytic performance. Therefore, development of new support materials for superior catalysis is of great importance. Here the synthesis of carbon nanofibers based on the reaction between phosphorus pentoxide (P 2 O 5 ) and N-methyl-2-pyrrolidone (NMP) is reporte...
Graphene, a 2-dimensional material, has received increasing attention due to its unique physicochemical properties (high surface area, excellent conductivity, and high mechanical strength). Field-effect transistor is shown to be a very promising candidate for electrically detecting chemical and biological species. Most of the reports on graphene field-effect transistors show that solution-gated graphene field effect transistors have been used so far. Although the traditional solution-gated graphene field effect transistor has high sensitivity, but the graphene channel is contaminated easily. The stability of the device is reduced so that the device cannot be reused. Only very recently, has the top-gated graphene, which is potentially used for pH sensors, been reported. In the top-gated graphene the dielectrics is deposited at the top of graphene. However, the sensitivity is lower than other sensors. To improve the properties, we design and fabricate a top-gated graphene ion-sensitive field effect transistor by using large-area graphene synthesized by chemical vapor deposition. At the top of graphene, HfO2/Al2O3 thin film is deposited by atomic layer deposition. The Al2O3 film plays a role of sensitive membrane, and the HfO2/Al2O3 thin film protects the graphene from contamination of the solution. After depositing the top-gate, because of the shield of the insulation, the boundary between the graphene and the substrate is not clear. And the Raman spectrum indicates the presence of a defective top layer accompanied by an increase in the Raman D peak. After a series of electrical characterizations, compared with solution-gated graphene field effect transistor which directly contacts the graphene channel with the solution, the top-gated graphene ion-sensitive field effect transistor has a high resistance. This increase relative to uncovered grapheme, is attributed to the participation of the top -orbitals in van der Waals bonds to the insulation. The graphene -orbitals contributing to van der Waals bonds have less overlaps and thus result in reduced conductivity. However the output curves and transfer curves show that the top-gated graphene ion-sensitive field effect transistor has higher signal-to-noise ratio and better stability. In view of the biochemical detection, in this paper we also examine the adsorption of single-stranded DNA. Silane functionalization of metal oxide system is a versatile technique that can be used in DNA microarray and nanotechnology. The DNA immobilization process we have developed contains several steps: silanization (APTES), crosslinker attachment (EDC and NHS), reaction with carboxyl-DNA and removal of non-covalently bound DNA. We characterize the process with carboxyl-quantum dots. We also measure the transfer curves before and after the adsorption of DNA, and demonstrate the effectiveness of the functionalized process and the feasibility that the top-gated graphene ion-sensitive field effect transistor is used as the biosensor.
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