The synthesis of Ag-polypyrrole nanocomposite coated latex particles and their application as a fluorescent quenching agent

Multifunctional screen-printed films using polymer nanocomposite based on PPy/TiO2: conductive, photocatalytic, self-cleaning and antibacterial functionalities

In this work, two electrically conductive samples based on polypyrrole (PPy) and (PPy/TiO₂) were synthesized via mini-emulsion polymerization. Synthesized samples were used as functional fillers to formulate two different screen-printing pastes (pastes A and B) to obtain the multi-purpose printed films with excellent properties, including electrical conductivity, antibacterial, photocatalytic activity, and self-cleaning. The surface tension, pH, and conductivity measurements validated the acceptable features of the produced pastes. Because of the shear-thinning behavior and viscosity buildup properties of the produced pastes, rheological investigations confirmed their potential for screen-printing. According to I–V test results, the optimum sintering temperature was chosen as a function of electrical conductivity, and the properties of the printed patterns were investigated by varying the printing sequences as 3, 6, and 9 times and sintered at the optimum temperature (90 °C). The contact angle of water on the optimum sample printed by Paste B was ca. 127° and relatively higher than the counterpart printed by Paste A which verified the superiority of the self-cleaning properties of the printed films with latter paste over the former. The photocatalytic studies concerning the degradation of methylene blue showed that the removal percentage of ca. 63% was achieved within the first 90 min of performing the test under UV light. The photocatalytic printed film was addressed the issue of filtering the unused suspension of nanoparticles, which made it difficult to remove the particles from the treated wastewater, in terms of sustainability. The fabricated patterns using Paste B exhibited improved properties, including electrical conductivity, antibacterial and photocatalytic activity.

Interfacial chemical oxidative synthesis of multifunctional polyfluoranthene

A novel polyfluoranthene (PFA) exhibiting strong visual fluorescence emission, a highly amplified quenching effect, and widely controllable electrical conductivity is synthesized by the direct cationic oxidative polymerization of fluoranthene in a dynamic interface between n-hexane and nitromethane containing fluoranthene and FeCl3, respectively. A full characterization of the molecular structure signifies that the PFAs have a degree of polymerization from 22-50 depending on the polymerization conditions. A polymerization mechanism at the interface of the hexane/nitromethane biphasic system is proposed. The conductivity of the PFA is tunable from 6.4 × 10-6 to 0.074 S cm-1 by doping with HCl or iodine. The conductivity can be significantly enhanced to 150 S cm-1 by heat treatment at 1100 °C in argon. A PFA-based chemosensor shows a highly selective sensitivity for Fe3+ detection which is unaffected by other common metal ions. The detection of Fe3+ likely involves the synergistic effect of well-distributed π-conjugated electrons throughout the PFA helical chains that function as both the fluorophore and the receptor units.