Sun Zhuangzhi,Du Shanqi,Li Fei,Yang Lu,Zhang Dan,Song Wenlong
A nanocomposite soft actuator based on porous high-conductivity electrode membrane, which was composed of biopolymer cellulose mixed with chitosan and highly conductive nanoparticles generated by reduced graphene oxide encapsulated multi-walled carbon nanotube, was developed in this paper. No new substance was discovered in the regenerated electrode layer through the scanning analysis from FT-IR and XRD. Actuators exhibited significant enhancement in peak to peak displacement, which was 3.64 times increased than the traditional value at 5 V 0.1 Hz. With the test of solid-state electric double layer capacitor, actuators showed the highest specific capacitance (10.695 F g −1 ) at the current density of 1 A g −1 , the lowest internal resistance (9.2 Ω g −1 ) in the frequency range of 10 5 –10 −2 Hz, and the lowest energy density (901 Wh kg −1 ) at the current density of 10 A g −1 , which demonstrated the absolute advantages in the conductivity and channels for electrons. These findings suggest that research on porous high-conductivity electrode layer holds great promise in the further study of higher performance actuators.
Transition-metal compounds have received extensive attention from researchers due to their high reversible capacity and suitable voltage platform as potassium-ion battery anodes. However, these materials commonly feature a poor conductivity and a large volume expansion, thus leading to underdeveloped rate capability and cyclic stability. Herein, we successfully encapsulated ultrafine CoP and CoSb nanoparticles into rich N-doped carbon nanofibers (NCFs) via electrospinning, carbonization, and phosphorization (antimonization). The N-doped carbon fiber prevents the aggregation of nanoparticles, buffers the volume expansion of CoP and CoSb during charging and discharging, and improves the conductivity of the composite material. As a result, the CoP/NCF anode exhibits excellent potassium-ion storage performance, including an outstanding reversible capacity of 335 mA h g −1 , a decent capacity retention of 79.3% after 1000 cycles at 1 A g −1 and a superior rate capability of 148 mA h g −1 at 5 A g −1 , superior to most of the reported transition-metalbased potassium-ion battery anode materials.
A new strategy for signal amplification was introduced in a label-free amperometric immunoassay platform. Improvements in the signal occurred following the oxidation of glucose by glucose oxidase and catalysis by polythionine of the produced H 2 O 2 from the previous oxidation reaction. In addition, a multifunctional conductive hydrogel, polypyrrole-polythionine-gold with glucose oxidase , was synthesised with a one-pot method using pyrrole and thionine as monomers, ammonium persulfate and HAuCl 4 as co-oxidant agents, and glucose oxidase as the doping agent. Combined with the hydrogel, a label-free amperometric immunoassay for the tumour marker neuron-specific enolase (NSE) was obtained. If operated at 0 V (vs. Ag/AgCl), the sensor exhibited a wide liner range from 100 ng mL −1 to 1 pg mL −1 and ultralow detection limit of 0.65 pg mL −1 (S/N = 3). The presented method was further used for the analysis of human serum samples and showed good consistency with detection results from an electrochemiluminescence immunoassay.
Ningxiao Yuan,Lu Xu,Bo Xu,Jianhao Zhao,Jianhua Rong
Chitosan derivative-based self-healable hydrogels with enhanced mechanical properties are reported, which were prepared by polymerization of acrylic acid (AAc) in 2-hydroxypropyltrimethyl ammonium chloride chitosan (HACC) solution. The PAAc/HACC hydrogels exhibit tensile fracture stress as high as 3.31 MPa and a Young's modulus of 2.53 MPa. They can maintain their original shape after 30 repeated compression cycles under various strain conditions, with a compression stress of more than 60 MPa at 99% strain. The damaged PAAc/HACC hydrogels can heal together in the presence of a NaCl salt solution with a self-healing efficiency of up to 61%. In addition, the PAAc/HACC hydrogels have high ionic conductivity and can serve as electrolytes for supercapacitors. The analysis suggests that all these good properties of the PAAc/HACC hydrogels mainly result from their high-density dynamic ionic interactions structure.
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