While extensively employed in electronic packaging, the prevailing electrically conductive adhesives (ECAs) are currently constrained by their lack of flexibility, excessive manufacturing costs, and limited multifunctionality. In this work, the antimony-doped tin oxide flexible conductive adhesives (AFCAs) were prepared by incorporating the antimony-doped tin oxide (ATO) nanoparticles into a thermoplastic polyurethane (TPU) matrix along with silver flakes. The ATO nanoparticles acted as conductive bridges for sliver flakes to enhance the electrical conductivity and mechanical integrity of the composites. The AFCAs formulated with a mere 60 % Ag and 7 % ATO nanoparticles exhibited an exceptionally low volume resistivity of 2.01 x 10-5 Omega & sdot;cm. After 10,000 mechanical bending cycles, the resistance change of AFCAs was only 8 %. Remarkably, the AFCA films also demonstrated excellent infrared stealth capabilities by infrared thermal imaging. This study demonstrates a facile strategy to develop high-performance and multifunctional AFCAs for flexible electrics with excellent electrical stability and infrared stealth capabilities.

Pressure-sensitive paints (PSP) enable non-intrusive visualization of surface pressure distribution on model surface which is important for aerodynamic studies. However, conventional PSP materials suffer from photobleaching and inadequate sensitivity. In this work, we rationally designed and synthesized novel dendritic oxygen probes (PT1 and PT2) by covalently grafting fluorinated dendrons onto platinum tetrakis(pentafluorophenyl)porphyrin (PT0) (a common oxygen probe). Subsequently, PT2 loaded nanofibers membranes from polycaprolactone (PCL) were fabricated by electrospinning. Fabricated membranes showed high oxygen sensitivity (I0/I100 = 35.3) with excellent flexibility, good reversibility, and outstanding photostability (merely 2.0% intensity loss after prolonged irradiation). The pressure sensitivity was found around 0.73 % per kilopascal. Furthermore, significant variation in emission intensity with respect to the variation in air pressure (1.3-101.32 kPa), facilitates the naked eye visualization of the pressure distribution on the membrane surface. Such excellent oxygen and pressure sensitivity and photostability might be due to high fluorine contents of complex dendritic structure of PT2. This flexible fluorine-functionalized dendritic oxygen probe puts forward a facile and effective strategy to develop advanced PSP materials enabling accurate pressure mapping for aerodynamic studies.

There is an increasing demand for monitoring ammonia in livestock farming, which can prevent livestock products from being contaminated by bacteria and viruses. As a prospective material for resistive sensors, polypyrrole (PPy) still suffers from low sensitivity and poor selectivity. Herein, zinc-tetra(p-sulfonylphenyl) porphyrin (Zntpp) particles are anchored on the PPy network by a one-step mild electrodeposition route to form a resistive sensor with the wrinkle-like nanostructure. The optimal PPy/Zntpp (Pzt) sensor demonstrates an outstanding response value of 104.3 % toward ammonia with a response/recovery time of 42/223 s, compared with that of PPy (7.2 % in response and 47/230 s). The durability and stabilities have been explored, and the limit of detection for Pzt is calculated to be similar to 8.63 ppm, which enables trace ammonia in livestock farming. Additionally, the sensing mechanism can be attributed to the p-n heterojunction. Furthermore, a wireless sensor device that consists of a Pzt sensory unit, a microcomputer, and a Bluetooth module is assembled, and the concentration information can be read precisely in real-time by a smartphone, indicating the great application prospects in the field of livestock farming.

The use of core-shell conductive microspheres as conductive fillers for anisotropic conductive films (ACFs) has broad application prospects for high-precision circuit connections. However, existing preparation methods suffer from environmental pollution and a relatively long processing procedure. Therefore, we propose a bio-inspired, simple, and environmentally friendly method for preparing PS/Ni core-shell conductive particles suitable for ACFs. Specifically, this study utilized the oxidative self-polymerization of dopamine (DA) to modify the surface of polystyrene (PS) microspheres. The catechol groups in polydopamine (PDA) act as both reducing agents and anchor groups for palladium (Pd) atoms to catalyze the electroless nickel plating. Results indicated that the amount of (PDA) on the PS surface and the morphology of the formed nickel-phosphor (Ni-P) layer were regulated by adjusting the DA polymerization time and concentrations. The prepared PS-PDA/Ni conducting particles with an average diameter of 2 +/- 0.2 mu m has a low density (1.5 g/cm3) and can be applied to ACFs. The application of the prepared ACFs was demonstrated by bonding two flexible print circuits (FPC) with a line spacing of 200 mu m. Good adhesion, conductivity, and anisotropic properties were observed in the bonded FPC200s. This study provides useful information for producing suitable conductive particles with easy synthesis for ACFs applications.

Polyaniline (PANI) is one of the best-known conductive polymers that has been widely studied due to its ease of synthesis, low cost, and tunable conductivity. However, it is still challenging to synthesize dispersible and highly electroconductive PANIs with high aspect ratios. This research provides a facile onestep synthetic method assisted by an organic dye, methyl orange (MO), to obtain high aspect ratios (the ratio could reach 20) in PANI structures. The presence of MO contributes to microtubes' morphology, enhancing their electrical conductivity from 0.5 to 4.6 S cm(-1), which is 8 times that of spherical PANI nanoparticles. The electrical properties and processability of the PANI microtubes were well explored simultaneously. The PANI microtubes can reach high conductive levels and maintain stable electrical performance for over 30 days. In addition, the PANI microtubes could be dispersed in a wide range of organic solvents and water. These functionalities enable them to act as conductive fillers to be effectively combined with silver flakes in thermoplastic polyurethane resins for fabricating conductive composites. Adding the PANI microtubes combined with silver flakes as conductive fillers in polyurethane, the resistivity of the composites can decrease to 1/1900 of those filled only with the same mass ratio of silver flakes, showing their great potential in reinforcing resins.

There is an increasing demand for sensitive, selective, and convenient detection tools for disease-related biomarker, potassium ion (K+). Electrospinning nanofibrous film as a novel sensing platform exhibits unique advantages due to high surface area ratio and network structure. In this study, electrospinning technique was employed to construct poly(vinyl alcohol) (PVA) nanofibrous film to assist K+ sensing. To find the best recipe, these factors including probe concentration, solvent composition, spinning time and cross-linking time were explored, and 8 groups of sensing films (F0-F7) were obtained in which F2 was considered the best and used for subsequent tests. Under optimized conditions, the sensing platform F2 was constructed by relatively continuous, uniform fibers with diameters in the range of 150???250 nm, and showed excellent selectivity, reusability, considerable response speed, and high sensitivity in which the fluorescence enhanced factor was as high as 8.9 with 10 mM K+. Moreover, F2 showed high accuracy in real samples detection, and it was used as a real-time K+ sensing platform. The excellent performance of F2 not only proved the reasonable design principle using PVA fibers for K+ sensing, but also could be extended to other probes and lead to different selectivity which was significant for biological diagnosis.

Bismuth (Bi) metallic material is one of the most widely used heavy metals because of its low cost, excellent light conversion efficiency, and high X-ray attenuation coefficient. However, large-scale synthesis of highly processable and oxidation-resistant Bi nanoparticles remains challenging. Based on the above concerns, we report a facile, scalable, polyol-mediated synthesis of high-quality Bi nanoparticles using citrate as a capping agent and polyvinylpyrrolidone (PVP) as a dispersant. The presence of citrate and PVP improved Bi nanoparticle's oxidation resistance and processability. These nanoparticles can maintain excellent oxidation resistance in an ambient atmosphere for more than 120 days and form high-quality suspensions in various commonly used solvents. Moreover, large-scale and rapid synthesis of the nanoparticles was achieved by simply using the green reagent stannous citrate [tin (II) citrate] as a reducing agent. These properties make them promising as complementary conductive fillers in electrically conductive adhesives (ECAs). The Bi nanoparticles could be effectively combined with silver flakes in epoxy resins to enhance the conductivity of ECAs significantly. With the addition of only 5 wt % Bi nanoparticles, the resistivity of ECAs could be reduced to 1/3000 of that of ECAs with the same silver content, showing great promise in next-generation ECA products.

Nanomaterials are at the forefront of next-generation sensing technologies because of their unique and tunable properties. For monitoring trace ammonia (NH3) in human metabolism, we synthesized a dual-emission nanoprobe with an average diameter of 4 nm by conjugating the NH3-sensitivity fluorescein derivative, the fluorescein isothiocyanate isomer (FITC, green emitter), onto the surface of carbon dots (CDs, blue emitter). A significant Forster resonance energy transfer (FRET) effect was observed, where the CDs acted as energy donors and FITC moieties acted as energy acceptors. The fluorescent color changed obviously from blue to green once ammonia was introduced into the test chamber. Subsequently, the dual-emission nanoprobe was immobilized in polyvinyl pyrrolidone nanofibers with an average diameter of 400 nm via electrospinning, thus obtaining a ratiometric NH3 sensor. Results showed that the fabricated sensor with a high surface area exhibited high sensitivity (theoretical detection limit was 0.53 ppm), short response time (similar to 4.3 s), excellent selectivity, and good reversibility in tracing 0-300 ppm NH3. Further prototyped application studies reveal that the sensor is expected to serve as an indicator for monitoring breath/blood ammonia concentration. Thus, the newly devel-oped fluorescent sensor was able to be a feasible solution for the application of nanomaterials in health and medicine.

To alleviating environmental problems and adapting to sustainable development, developing an efficient and flexible ammonia gas detection equipment remains a great challenge. A room temperature polyaniline/cobalt porphyrin (PANI/CoTPP) NH 3 gas sensor based on flexible ITO-PET substrate was prepared by one-step self-assembled electrodeposition method. We found that the electrodeposition of ANI and CoTPP destroyed the original dendritic structure in the molecular chain and led to the aggregation of a large number of massive particles, increasing the contact area between the sensor and NH 3 . Further, the introduced CoTPP not only had a moderate cooperative capture ability for NH 3 , but also emerged charge polarization effect when contacting with NH 3 . Therefore, the as-obtained flexible NH 3 sensor has excellent sensing response and recoverability. Its good response performance is demonstrated by the lower detection limit (LOD) of 0.83 ppm. The ability of CoTPP to capture NH 3 in PCT sensor is verified by DFT calculations with First-principles investigation. This work indicates that this well-designed PANI/CoTPP NH 3 gas sensor based on flexible ITO-PET substrate is a potential way to design ammonia gas sensors.

Dissolved oxygen (DO) sensors for the practical application usually require good resistance to complex and extreme environments, such as acidic or alkaline corrosion, seawater sediment erosion, protein or bacteria adhesion, etc. Diatom frustules (DFs) are protective shell structures extracted from diatoms, which have delicate hierarchical pores and a large specific surface area, showing their utilization potential as oxygen sensing materials. Herein, we developed a superhydrophobic DO sensor which use the DFs as matrix materials. The sensor was fabricated by spraying the mixture of 1 H,1 H,2 H,2 H-perfluorooctyltriethoxysilane (PFOTS) modified DFs and oxygen-sensitive probe platinum (II) 5,10,15,20-tetrakis-(2,3,4,5,6-pentafluorophenyl)-porphyrin (PtTFPP) on the bonding substrate. In the DO sensor, DFs provides a tough micro/nano surface structures and PFOTS offers low surface energy, both of which led to a robust superhydrophobic surface of the sensor. Because of the porous structure of DFs and the diffusion enhancement effect of fluorine on oxygen, the sensor has high DO sensitivity, I-0/I-100 which represents for oxygen sensitivity reaches up to 129. Additionally, the sensor showed good tolerance on mechanical abrasion, acidic or alkaline corrosion and biofouling. Owing to these good performances, the use of DFs is expected to provide a new strategy for the rational design of high performance DO sensing devices.

As one of the supercapacitor materials, nickel–vanadium layered double hydroxide (NiV‐LDH) has received wide attention, but poor electrochemical stability and capacitance constrain their applications. Carbon nanotubes (CNTs) enable solving these issues. Herein, NiV‐LDH@CNT is well designed and prepared through a facile one‐step refluxing method, which is free of high temperature and complicated equipment. Benefiting from the hierarchical and accessible structure, the NiV‐LDH@CNT composite indicates a high specific capacitance (1493 F g−1 at a current density of 1 A g−1 and 432 F g−1 at 50 A g−1). It also has 68.8% cycling durability after 1000 charge/discharge cycles at 20 A g−1, compared with that of NiV‐LDH of 28.1%. Furthermore, the asymmetric supercapacitors (ASCs) with activated carbon (AC) and NiV‐LDH@CNT are fabricated by the screen‐printing method. Surprisingly, the as‐fabricated NiV‐LDH@CNT//AC ASC device can achieve an ideal specific capacitance (85 F g−1 at 2 A g−1) and a large energy density (95.6 Wh kg−1 at a power density of 5417.8 W kg−1), which can be a great promising candidate for electrodes in the energy storage device.

The colorimetric sensing label is a simple, cost-effective, and user-friendly tool for monitoring ammonia vapor (NH3) concentrations in food packaging. Numerous natural dyes present excellent NH3-sensitivity, but their low solubility in water limits their food-related applications. Herein, a special cellulose-based ink system with an EtOH/water mixture as solvent was proposed to improve the dispersion of non-aqueous dyes (curcumin and its analogs (indexed as Bur and Bur-BF2)). Subsequently, three sensing labels containing different dyes were prepared by simple screen-printing after optimizing the inks' rheological properties. Benefiting from the different intramolecular charge-transfer (ICT) behaviors of dyes, each sensing label exhibited various characteristics in terms of the optical property, NH3-sensitivity, and fluorescent color-changing routes upon exposure to 0-50 ppm NH3. Importantly, all sensing labels showed excellent stability in environments with various relative humidity and temperature. Therefore, three sensing labels were used to construct a multicolor fluorescent sensor array, which aimed to visually monitor the freshness of shrimp for consumers.

Poly(3,4-ethylene dioxythiophene) (PEDOT) is widely used in electronics for its excellent conducting property. However, it is challenging to synthesize PEDOT nanoparticles with high conductivity and high dispersibility in various organic solvents. We introduce a novel strategy for synthesizing highly conductive, dispersible PEDOT particles in a binary organic solvent system. The synthesis strategy is based on a standard chemical oxidation procedure, which uses ferric chloride (FeCl3) as the oxidant without any post-doping process in a mixed solvent of dichloromethane and acetonitrile (CH2Cl2 and CH3CN). By optimizing the synthesis process, high-quality colloidal PEDOT nanoparticles (average diameter is around 50 nm) are obtained with a high yield of over 75%. These nanoparticles show a maximum electrical conductivity of 220 S/cm, which is close to the highest electrical conductivity of the current solid PEDOT powder. Moreover, these particles can be dispersed in various organic solvents and water without a surfactant and maintain stable conductivity for over one month. This outstanding processability and conductivity could reinforce thermoplastic polyurethane resins as conductive composites. Prototyped applications of the PEDOT nanoparticles as supercapacitor materials are demonstrated. The PEDOT nanoparticles show a high specific capacitance of 280 F/g, comparable to other reported PEDOT materials prepared using various templates.

There is an increasing demand for monitoring ammonia in livestock farming, which can prevent livestock products from being contaminated by bacteria and viruses. As a prospective material for resistive sensors, polypyrrole still suffers from low sensitivity and poor selectivity. Herein, polypyrrole/zinc-tetra(p-sulfonylphenyl) porphyrin (Pzt) loaded on ITO-PET is successfully synthesized by a one-step mild electrodeposition route. In the hybrid, Zntpp particles are anchored on the PPy network, forming a ravine-like nanostructure that is ideal for gas detection, and the response performances have supported this hypothesis. Remarkably, the optimal Pzt demonstrates an outstanding response value of 104.3 (S/%) toward ammonia with a response/recovery time of 42/223 s, compared with that of PPy (7.2 in response and 47/230 s). The mechanical properties and stabilities have been studied, and the limit of detection for Pzt is calculated to be ~8.63 ppm, which enables trace ammonia in livestock farming. Additionally, the mechanism is attributed to p-n heterojunction. Furthermore, a wireless sensor device that consists of a Pzt sensory unit, a microcomputer and a Bluetooth module is assembled, and the concentration information can be read precisely in real-time by a smartphone, indicating the great application prospects in the field of livestock farming.

Electrically conductive adhesives (ECAs) are a kind of attractive alternative to tin solders in microelectronics. However, fabricating high-performance, low-cost ECAs remains challenging due to the need for high-content metal fillers. This work reported a facile preparation of cost-effective ECAs composed of aluminum-doped zinc oxide (AZO) nanoparticles and silver (Ag) micro-flakes. The AZO nanoparticles could serve as a "bridge" to connect neighboring Ag micro-flakes to significantly improve the ECAs' conductivity (from 1638.8 x 10(-5) Omega.cm to 8.5 x 10(-5) Omega.cm). After the aging and bonding performance tests, prototyped applications of the as-prepared ECAs for three flexible electronic devices were demonstrated sequentially: (I) The resistance of flexible conductive film showed excellent dynamic stability after being folded for 1000 cycles, bent/released within 6 mm radius for more than 2000 cycles, or applied with 1000 kPa pressure; (II) The coil antenna achieved fast transmission of radio frequency signal for near field communication (NFC) system; (III) The flexible heater performed efficient thermal management at 0.4-1.4 V input voltages. Therefore, the fabricated ECAs are expected to provide new opportunities for the development of novel flexible electronic devices for future applications.

Conductive polymer composites (CPCs) with high conductivity and flexibility play a crucial role in emerging flexible electronics. However, the facile fabrication of high-performance flexible conductors is still challenging due to cumbersome manufacturing steps and the need for expensive metal nanomaterials as conductive fillers. Herein, we presented a facile and cost-effective method to prepare CPCs with an ultralow resistivity of 2.4 x 10(-5) Omega.cm at 60% silver micronflakes. The elastic CPCs are simply composed of conductive cofillers of commercial silver micronflakes and polyaniline/halloysite nanotubes (PANI/HNTs) and water-based polyurethane (WPU) resin as the matrix. With a delicate design, the PANI/HNTs could locate adjacent silver micronflakes in the WPU resin and form conducting paths to improve the electrically conductive performance of the composites significantly. Thus, the CPCs serve as flexible conductors showing high conductivity and excellent stability during numerous cyclic mechanical deformations, such as bending, stretching, twisting, and folding. These advantages make the valuable materials candidates for the next generation of flexible conductors.

Herein, we report high-performance electrically conductive adhesives (ECAs) as promising materials for flexible conductive films, printed circuits, and electromagnetic interference shielding devices. Through combining a small amount of water-dispersible polyaniline (PANI) nanorods and silver flakes into water-based polyurethane (WPU), the obtained ECAs showed high electrical conductivity with a low Ag content (4.8 × 10 4 S/cm, 60 wt% of silver, and 6% PANIs) and excellent stability; this stability withstood aging without change at 85 °C/65% RH for at least 20 days. Prototyped applications of the ECAs for flexible conductive films, printed circuits, and electromagnetic interference shielding devices were demonstrated. When these ECAs were used as flexible conductive films, these films exhibited excellent electrical performance under high mechanical deformation. The resistance of films remained unchanging after being bent with a 6-mm radius for over 8000 cycles, applied with 1000 kPa pressure, or stretched 20% for over 1000 cycles. The printed circuits had excellent flexibility and good adhesion on flexible substrates, enabling the circuits’ stable operation at a high deformation. Moreover, novel conductive foams with high conductivity of 283.4 S/m and reasonable electromagnetic interference shielding effectiveness (EMI SE) of above 34 dB were obtained by integrating the ECAs with PU sponges to broaden the applications of ECAs. Therefore, this study provided an original, uncomplicated, low-price route to fabricate high-performance ECAs based on water-soluble resins for various flexible electronic devices.

Carbon nanotube (CNT) shows great potential in ammonia detection, but the drawback of low selectivity and poor sensitivity has persisted. Here, zinc-tetra (4-sulphonatophenyl) porphyrin (ZnTPP) is employed as a sensitizer, and the binder-free ZnTPP/CNT paper is obtained via a wet-papermaking technology and hot-pressing process. In the compound, ZnTPP anchored firmly on the CNT by means of the H-bonding and/or $\pi $ - $\pi $ conjugation, paper fibers and CNT/ZnTPP are served as the framework and “slurry,” respectively, generating the binder-free 3-D structure. Benefiting from the charge transfer process by the “interchange” of ZnTPP, the optimal ZnTPP/CNT paper (ZCP-2) indicates an outstanding selective, excellent stability, and good cycling response (162 and 531 s in response and recovery time) to NH 3 . This work paves a new strategy for the improvement of the CNT-based material, which is meaningful for the field of ammonia sensors used in concentration calibration.

以壳聚糖为原料,采用水热法一步制备水溶性的荧光碳量子点(CQDs),考察反应条件(壳聚糖质量浓度、温度和时间)对CQDs产物表面官能团和产率的影响,采用TEM、FTIR、XRD、UV-Vis和PL等技术对其形貌、结构和性能进行了表征,并探究其在防伪领域的应用.结果表明,当壳聚糖质量浓度为10 g/L,温度为180℃,时间为12 h时,制得的CQDs结构完整且产率较高;CQDs微观表现为球状纳米颗粒,直径约为36.2 nm,表面伴有羟基和氨基官能团;制得的CQDs在293和330 nm处均有吸收峰,表现为蓝色荧光,荧光量子产率约为39.8％.将其配制成墨水后,结合喷墨印刷,在自然光和紫外光下可有效实现加密信息的"显"和"隐",具有较好的防伪效果.

A novel colorimetric indicator for pork freshness composed of agar, ZnTPPS 4 and glycerin was designed and developed by casting/solvent evaporation method. The FT-IR, UV-vis, XRD and SEM were employed to analyze the structure and valence bonds of ZnTPPS 4 /AG compound, and the results showed good compatibility between agar and ZnTPPS 4 . The tensile strength and elongation at the breaking point of indicator films increased slightly with increase of porphyrin, which may have been a contributing factor of H-bonds. After 7 days of placement, the total color variation ([Formula: see text]E) of major films was less than 5, manifesting in the color stability being sufficient enough to act as a color indicator, and the mechanism for color variation was explained therein. Furthermore, the prepared films were utilized as indicators for monitoring the freshness of lean meat at room temperature (25[Formula: see text]C). The total volatile basic nitrogen (TVB-N) of pork and [Formula: see text]E of the labels were recorded simultaneously. The trials demonstrated that ZnTPPS 4 /AG with higher content of ZnTPPS 4 had the superior sensitivity and the color changes of labels in pork packaging changed according to the decay threshold of TVB-N, which implied that ZnTPPS 4 /AG was able to indicate the spoilage via colorimetric method. Therefore, these novel indication labels could be used to monitor the pork freshness in a real-time, nondestructive and inexpensive way.