Ambient fine particulate matter (PM) affects both human health and climate. To reduce the PM2.5 (mass of particles below 2.5 μm in diameter) concentration of an individual's living environment, ionic liquid-modified polyacrylonitrile (PAN) nanofibers with superior PM2.5 capture capacity were prepared by electrospinning. Ionic liquid diethylammonium dihydrogen phosphate (DEAP) with high viscosity and hydrophilicity was involved during the electrospinning process. Observations by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and water contact angle measurement suggested that the modification of DEAP on PAN effectively altered the morphology (roughness) and surface properties (hydrophilicity) of the PAN nanofibers. The PM2.5 capture measurement was performed in a closed and static system, which mimicked the static hazy weather without wind flow. As a result, DEAP-modified PAN nanofibers exhibited significantly enhanced PM2.5 capture capacity compared to that of the bare PAN nanofibers. This can be attributed to the improved surface roughness (i.e., improved adsorption sites), hydrophilicity, and dipole moment of PAN upon DEAP modification.
Highlights • Bimetallic Au@Pt nanoparticles as core-shell structures demonstrate the enhanced catalytic performance for glucose oxidation. • Nafion layer and dendritic Pt shells prevent passivation of the Au core and additional Au plating further enhances catalytic performance. • Rationally designed Au-decorated Au@Pt NPs show enhanced sensitivity, stability, and selectivity towards glucose detection.
We developed a novel strategy for fabricating poly(3,4-ethylenedioxythiophene) (PEDOT) patterns on various substrates, including hydrogels, via sequential solution procedure without multistep chemical etching or lift-off processes. First, PEDOT nanothin films were prepared on a glass substrate by solution phase monomer casting and oxidative polymerization. As a second step, after UV-induced poly(ethylene glycol) (PEG) photolithography at the PEDOT/PEG interface through a photomask, the hydrogel was peeled away from the PEDOT-coated glass substrate to detach the UV-exposed PEDOT region, which left the UV nonexposed PEDOT region intact on the glass substrate, resulting in PEDOT patterns. In a final step, the PEDOT patterns were cleanly transferred from the glass to a flexible hydrogel substrate by a direct-transfer process based on a second round of gelation process. Using this strategy, PEDOT patterns on ITO glass or ITO film were used to successfully fabricate an electrochromic (EC) device that exhibited stable electrochromic switching as a function of applied potential. Furthermore, PEDOT patterns on hydrogel were used to fabricate all organic, flexible microelectrodes with good electrical properties and excellent mechanical flexibility. Importantly, the conductivity of PEDOT patterns on hydrogel (ca. 235 S cm) described here is significantly higher than that previously reported (ca. 20-70 S cm). This approach can be easily integrated into various technological fabrication steps for the development of next-generation bioelectronics systems.
Dendritic platinum nanoparticles (DPNs) have been synthesized from l-ascorbic acid and an amphiphilic non-ionic surfactant (Brij-58) via a sonochemical method. The particle size and shape of the DPNs could be tuned by changing the reduction temperature, resulting in a uniform DPN with a size of 23 nm or 60 nm. The facets of DPNs have been studied by high-resolution transmission electron microscopy. The cytotoxicity of DPNs has been investigated using human embryonic kidney cells (HEK-293), and the biological adaptability exhibited by DPNs has opened a pathway to biomedical applications such as drug-delivery systems, photothermal treatment, and biosensors.
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