Phosphonate-Functionalized Polyfluorene Film Sensors for Sensitive Detection of Iron(III) in both Organic and Aqueous Media

A novel conjugated polymer (CP) based thin film sensor toward Fe3+ was prepared by covalent immobilization of a phosphonate-functionalized polyfluorene on glass surface. Contact angle, XPS and steady-state fluorescence measurements proved that the polyfluorene was successfully chemically conjugated on the substrate surface. Like the organic solution and spin-casting film of this polyfluorene, the fluorescence of the immobilized film can be selectively quenched by Fe3+ in both organic and aqueous solutions. Limit of detection of this film sensor for Fe3+ could be down to 8.4 ppb in THF solution and 0.14 ppm in aqueous solution, which were among the best results for Fe3+ sensing by fluorescence film sensors reported so far. Compared with the fluorescence quenching properties of the same polyfluorene in THF solution and in spin-casting film, both quenching constant and detection limit of the immobilized film were improved by 1 order of magnitude, which demonstrated the advantage of the immobilized film fluorescence sensor. In addition, the sensing process is reversible in both organic and aqueous solutions

Highly Selective and Sensitive Detection of Cyanide by a Reaction-Based Conjugated Polymer Chemosensor

Based on a specific nucleophilic addition reaction with cyanide, a dicyano-vinyl-containing conjugated polymer (P1) has been designed and synthesized as a colorimetric and fluorescent chemosensor for cyanide anion. The combination of advantages of both reaction-based sensors and conjugated polymer sensors offers its highly sensitive and selective recognition of CN–. The addition of CN– to P1 solution induced a change in the solution color from yellow-green to colorless, while no color change could be observed in presence of other common anions, by which CN– can be identified from other anions directly with the naked eye. At the same time, a 31.6-fold fluorescence quenching was achieved upon adding CN– into P1 solution. The fluorescence quenching has shown a linear response to CN– in the concentration range of 0.5–30 μM. Furthermore, its detection limit for CN– can be as low as 14 ppb, which is among the best results for the fluorescent conjugated polymer-based cyanide chemosensors. Compared with its small molecular counterpart, P1 exhibits higher sensitivity and selectivity, wider linear region, and faster response

Amino Acid-Functionalized Polyfluorene as a Water-Soluble Hg²⁺ Chemosensor with High Solubility and High Photoluminescence Quantum Yield

Amino Acid-Functionalized Polyfluorene as a Water-Soluble Hg2+ Chemosensor with High Solubility and High Photoluminescence Quantum Yiel

Selective Detection of TNT and Picric Acid by Conjugated Polymer Film Sensors with Donor–Acceptor Architecture

Selective Detection of TNT and Picric Acid by Conjugated Polymer Film Sensors with Donor–Acceptor Architectur

Solubility Isotherms of Gypsum, Hemihydrate, and Anhydrite in the Ternary Systems CaSO₄ + MSO₄ + H₂O (M = Mn, Co, Ni, Cu, Zn) at <i>T</i> = 298.1 K to 373.1 K

The solubilities of anhydrite in the ternary systems CaSO₄ + MSO₄ + H₂O (M = Co, Ni) were determined through isothermal solution saturation at 348.1 K and 363.1 K. At low bivalent metal sulfate concentrations, anhydrite solubility decreases until it eventually reaches a minimum. Anhydrite solubility subsequently increases with the amount of heavy metal sulfate to a maximum. At this point, further increases in the concentration of metal sulfate decreases the solubility of anhydrite until saturation of the added bivalent metal sulfate. A Pitzer thermodynamic model was selected to predict isopiestic data including calcium sulfate solubilities of the ternary systems CaSO₄ + MSO₄ + H₂O (M = Mn, Co, Ni, Cu, Zn) from 298.1 K to 373.1 K. The functional dependencies of the MSO₄ (M = Ni, Cu, Zn) ion interaction parameters with temperature were determined, and the third virial parameters were given. The calculated solubilities are in agreement with the available experimental data. Using the Pitzer model and parameters, the solubility isotherms of metastable solid-phase hemihydrate, as well as gypsum and anhydrite, in the CaSO₄ + MSO₄ + H₂O (M = Mn, Co, Ni, Cu, Zn) systems were predicted over a wide range of temperatures and concentrations

Efficient Purely Organic Room-Temperature Phosphorescence from Selenium-Containing Conjugated Polymers for Signal-Amplified Oxygen Detection

Purely organic room-temperature phosphorescent (RTP) polymers with good processability and flexibility over small molecular crystals are highly attractive. Although many non-conjugated polymers (non-CPs) with efficient RTP emission have been reported, the development of metal-free RTP CPs remains a formidable challenge. Herein, CPs with clear RTP emission in both doped and neat films are readily prepared by introducing a selenium-containing phenoselenazine unit into conjugated backbones. The resulting RTP CPs can achieve phosphorescence lifetimes ranging from microseconds to milliseconds and phosphorescence quantum yields of up to 17.2% in film states, representing the highest value for metal-free CPs. Moreover, these RTP polymer films can be used for ratiometric oxygen detection due to their sensitive RTP emission to oxygen. Remarkably, for the first time, these metal-free CPs demonstrate significant phosphorescent signal amplification with a Stern–Volmer quenching constant (KSV) value of up to 5.54 × 10–3 ppm–1, which is 250 times higher than that of their molecule counterpart