Nitrogen-and Oxygen-Containing Porous Ultrafine Carbon Nanofiber:A Highly Flexible Electrode Material for Supercapacitor

Herein, we report a simple and effective preparation of ultrafine CNFs （u-CNFs） with high surface area via electrospinning of two immiscible polymers [polyacrylonitrile （PAN） and poly（methyl methacry- late） （PMMA）] followed by calcination at high temperature in an inert atmosphere. Various electrospinning conditions were optimized in detail. Four different kinds of PAN/PMMA ratios （10/0, 7：3, 5：5 and 3：7） were chosen and found that the PAN/PMMA ratio of 3：7 （PAN/PMMA-3：7） is the optimum one. BET anal- ysis showed the specific surface area of the u-CNFs-3：7 was 46Z57 m2/g with an excellent pore volume （1.15 cms g-l） and an average pore size （9.48 nm）： it is about 25 times higher than the conventional CNFs （c-CNFs）. TEM and FE-SEM images confirmed the ultrafine structure of the CNFs with a thinner fiber di- ameter of-50 nm. The graphitic nature and atomic arrangement of the u-CNFs were investigated by Raman and XPS analyses. For the supercapacitor application, unlike the common electrode preparation methods, the u-CNFs-3：7 was used without any activation, chemical or mechanical modifications. The u-CNFs- 3：7 showed a better specific capacitance of 86 Fig in 1 mol/L 1-12S04 when compared to pure CNFs. The excellent physicochemical properties make the u-CNFs-3：7 an alternative choice to the existing CNFs for the supercapacitors.

Deformable Textile‑Structured Triboelectric Nanogenerator Knitted with Multifunctional Sensing Fibers for Biomechanical Energy Harvesting

Fibers and textiles that harvest mechanical energy via the triboelectric effect are promising candidates as power supplies for wearable electronics.However,triboelectric fibers and textiles are often hindered by problems such as complex fabrication processes,limited length,performances below the state-of-the-art of 2D planar configurations,etc.Here,we demonstrated a scalable fabrication of core-sheath-structured elastomer triboelectric fibers that combine silicone hollow tubes with gelelectrodes.Gel-electrodes were fabricated via a facile freeze–thawing process of blending polyvinyl alcohol(PVA),gelatin,glycerin,poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate)(PEDOT:PSS),and sodium chloride(NaCl).Such fibers can also be knitted into deformable triboelectric nanogenerator textiles with high electrical outputs up to 106 V and 0.8μA,which could work as reliable power supplies for small electronics.Moreover,we demonstrated fabric materials recognition,Morse code communication,and human-motion-recognition capabilities,making such triboelectric fiber platform an exciting avenue for multifunctional wearable systems and human–machine interaction.

A Simple Method for the Fabrication of Metallic Copper NanospheresDecorated Cellulose Nanofiber Composite

Herein, we report a new and simple method for the preparation of metallic copper nanospheres- decorated cellulose nanofiber composite （CuNSsJCNFs）. Initially, the cellulose acetate nanofibers （CANFs） were electrospun followed by deacetylation and anionization to produce functional anionic cellulose nanofibers ff-CNFs）. The CuCl2 precursor was deposited on thef-CNFs （CuC12/CNFs） by a simple dipping method. Then the CuCIdCNFs were reduced under vacuum by using aluminum foil to produce the CuNSs/ CNFs. The resultant CuNSs/CNFs composite was characterized by various microscopic and spectroscopic methods. Fourier transform infrared spectroscopy （FT-IR） confirmed the successful functionalization of anionic groups with the CNFs. The field emission scanning electron microscopy （FE-SEM） and transmission electron microscope （TEM） results confirmed the formation of CuNSs on the surface of CNFs. From the scanning electron microscopy-energy dispersive spectroscopy （SEM-EDS） analysis, the weight percentage of Cu was found to be 23.5 wt%. The successful reduction of CuO to metallic Cu was confirmed by X-ray photoemission spectroscopy （XPS） and X-ray diffraction （XRD） analyses. Mechanism has been proposed for the formation of metallic Cu sphere on CNFs.

Reactive Dyeing of Electrospun Cellulose Nanofibers by Pad-steam Method

Based on the functional properties of electrospun cellulose nanofibers(CNF),scientists are showing substantial interest to enhance the aesthetic properties.However,the lower color yield has remained a big challenge due to the higher surface area of nanofibers.In this study,we attempted to improve the color yield properties of CNF by the pad-steam dyeing method.Neat CNF was obtained by deacetylation of electrospun cellulose acetate(CA)nanofibers.Three different kinds of reactive dyes were used and pad-steam dyeing parameters were optimized.SEM images revealed smooth morphology with an increase in the average diameter of nanofibers.FTIR results showed no change in the chemical structure after dyeing of CNF.Color fastness results demonstrated excellent ratings for reactive dyes,which indicate good dye fixation properties and no color loss during the washing process.The results confirm that the pad-steam dyeing method can be potentially considered to improve the aesthetic properties of CNF,which can be utilized for functional garments,such as breathable raincoats and disposable face masks.

Leaf-meridian bio-inspired nanofibrous electronics with uniform distributed microgrid and 3D multi-level structure for wearable applications

The interface between the active electronic and its osculatory target dominates the sensing response of high-sensitivity sensors.However,the interface properties are difficult to be adjusted and preserved owing to the limited strategies for surface engineering.In this work,inspired by nature frond leaf,a spatial multi-level nanofibrous membrane with grid-like microstructure of uniform distribution was fabricated,in which carboxylated carbon nanotubes(CCNTs)/poly(3,4-ethylenedioxythiophene)(PEDOT)was modified onto the surface of grid-like polyurethane(PU)nanofiber via the combination of metal mesh template,in situ polymerization and ultrasonic treatment.Nanofibrous membrane enables a pressure sensor with high sensitivities(5.13 kPa−1),fast response/recovery time(80 ms and 120 ms),and ultralow detection limit of 1 Pa.In addition,as a scalable and integrable platform,we also demonstrate its multifunctional applications for electro-thermal conversion and energy harvesting.All these results indicate the proposed nanofibrous membrane may potentially be applied to next-generation wearable devices.