Sulfonated poly(arylene thioether phosphine oxide)s copolymers for proton exchange membrane fuel cells

Abstract High molecular weight sulfonated poly(arylene thioether phosphine oxide)s (sPATPO) with various sulfonation degrees were prepared directly by aromatic nucleophilic polycondensation of 4,4 -thiobisbenzenethiol with sulfonated bis(4-fluorophenyl) phenyl phosphine oxide and bis(4-fluorophenyl) phenyl phosphine oxide. sPATPO in the acid form with sulfonation degrees of 60-100% exhibits a glass transition temperature higher than 230 • C and a 5% weight loss temperature above 400 • C, indicating high thermal stability. sPATPO with a high sulfonation degree shows high proton conductivity and good resistance to swelling as well. For instance, sPATPO-70 displays the conductivity of 0.0783 S/cm and a swelling ratio of 11.6% at 90 • C. TEM micrographs showed that sPATPO membranes with a high sulfonation degree could form continuous ion channels, which are favorable for improving the proton conductivity but harmful to remaining the mechanical property. The membranes are expected to show good performances in fuel cell applications

The Functional Fe₃O₄@SiO₂@AuNPs SERS Nanomaterials for Rapid Enrichment and Detection of Mercury Ions in Licorice

There has been an increasing demand for rapid and sensitive techniques for the detection of heavy metal ions that are harmful to the human body in traditional Chinese medicine (TCM). However, the complex chemical composition of TCM makes the quantitative detection of heavy metal ions difficult. In this study, the magnetic Fe3O4@SiO2@AuNPs nanoparticles combined with a probe molecule DMcT were used for the specific enrichment and detection of Hg2+ in the complex system of licorice. The core of Fe3O4 was bonded with SiO2 to increase its stability. A layer of AuNPs was deposited to produce a “core–shell” Raman substrate with high surface-enhanced Raman spectroscopy (SERS) activity, which was surface modified by DMcT probe molecules with sulfhydryl groups. In the presence of Hg2+, Hg2+ binds to N on the amino group of DMcT to form N-Hg2+-N complexes, which induces Fe3O4@SiO2@AuNPs-DMcT clustering to enhance SERS signal. The Raman probe molecule DMcT showed an excellent linear relationship (R2 = 0.9709) between the SERS signal at 1416 cm−1 and the Hg2+ concentration (0.5~100 ng/mL). This method achieved a good recovery (89.10~111.00%) for the practical application of detection of Hg2+ in licorice extracts. The results demonstrated that the functional Fe3O4@SiO2@AuNPs-DMcT performed effective enrichment and showed high sensitivity and accurate detection of heavy metal ions from the analytes