Rechargeable batteries paired with sodium (Na)-metal anodes are considered as one of the most promising high energy and low-cost energy storage systems. However, the use of highly reactive Na metal and the formation of Na dendrites during battery operation have caused signi cant safety concerns, especially when highly ammable liquid electrolytes are used. Herein, we design and develop a solventfree solid polymer electrolytes (SPEs) based on a per uoropolyether (PFPE) terminated polyethylene glycol (PEG)-based block copolymer for safe and stable all-solid-state Na-metal batteries. Compared with traditional poly(ethylene oxide) (PEO) or PEG SPEs, our results suggest that block copolymer design allows for the formation of self-assembled microstructures leading to high storage modulus at elevated temperatures with the PEG domains providing transport channels even at high salt concentration (EO/Na + = 8:2). Moreover, it is demonstrated that the incorporation of PFPE segments enhances the Na + transference number of the electrolyte to 0.46 at 80 o C. Finally, the proposed SPE exhibits highly stable symmetric cell cycling performance with high current density (0.5 mA cm -2 and 1.0 mAh cm -2 , up to 1300 hours). The assembled all-solid-state Na-metal batteries with Na 3 V 2 (PO 4 ) 3 cathode demonstrate outstanding rate performance, high capacity retention and long-term charge/discharge stability (CE = 99.91%) after more than 900 cycles.
Imaging agents that can be targeted to specific diseases and respond to the microenvironment of the diseased tissue are of considerable interest due to their potential in diagnosing and managing diseases. Here we report a new class of branched fluorinated glycopolymers as 19 F MRI contrast agents which respond to a reductive environment, for targeted imaging of cancer. The fluorinated glycopolymers can be readily prepared by a one-pot RAFT polymerization of glucose-and fluorine-containing monomers in the presence of a disulfide-containing crosslinking monomer. The incorporation of glucose units along the polymer chain enables these fluorinated glycopolymers to effectively target cancer cells due to interactions with the over-expressed sugar transporters present on the cell surface. In addition, the polymers exhibit an enhanced 19 F MRI signal in response to a reductive environment, one of the unique hallmarks of many cancer cells, demonstrating their potential as promising candidates for targeted imaging of cancer.
Surface-enhanced
Raman spectroscopy (SERS) is a promising analytical
tool, but simultaneous detection of multiple targets using SERS remains
a challenge. Herein, a cauliflower-inspired 3D SERS substrate with
intense hot spots was prepared through sputtering Au nanoparticles
(Au NPs) on the surface of polydimethylsiloxane coated anodic aluminum
oxide (PDMS@AAO) complex substrate. As a result, the cauliflower-inspired
3D SERS substrate achieved the highest SERS activities at a sputtering
time of 8 min. Under the optimal conditions, this SERS substrate possessed
a low detection limit of 10–12 M, excellent enhancement
uniformity (relative standard deviation, RSD = 4.57%) and high enhancement
factor (2.2 × 106) for 4-mercaptobenzoic acid (4-MBA).
Furthermore, the results of Raman showed that the 3D-Nanocauliflower
SERS substrates could realize the simultaneous label-free detection
for three mycotoxins (aflatoxin B1, deoxynivalenol, and
zearalenone) in maize for the first time. It behaved good linear relationship
between the concentrations and Raman intensities of aflatoxin B1, zearalenone, and deoxynivalenol. For the three mycotoxins,
this method exhibited the limit of detection (LOD) of 1.8, 47.7, and
24.8 ng/mL (S/N = 3), respectively. The 3D-Nanocauliflower SERS substrates
with dense hot spots presented remarkable SERS effect and activity,
which could be act as a potential candidate for SERS substrate applied
in the rapid and label-free detection.
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