Enhanced sensing and electrical performance of hierarchical porous ionic polymer-metal nanocomposite via minimizing cracks in electrode

High-performance foldable metal-coated ionic polymer-metal nanocomposites (IPMNCs) with crack minimized electrode are desired for wearable electronics, energy harvesting devices, tactile sensors, structural health monitors, humidity sensors, and supercapacitor devices. However, the IPMNC shows the cracked structure that seriously decreases the performance of IPMNCs for sensors and actuators applications. To overcome the issue of the cracked metal electrode, here we propose a metal-coated hierarchical porous structured IPMNC via minimizing the cracks in the Platinum (Pt) electrode using attachment of poly(2-acrylamide-2-methyl-1-propane-sulfonic acid) (PAMPS) in poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE))/polyvinylpyrrolidone (PVP) blend. The crack-minimized Pt electrode deposition on PAMPS attached P(VDF-TrFE)/PVP-based IPMNCs showed enhanced electrical and sensing signals compared to the Nafion, ionic liquid, and polystyrene sulphonic acid-based IPMNCs. The developed IPMNCs with an optimized composition depict stable sensing signals up to 10,000 cycles. The hierarchical porous structure and the crack-minimized metal electrode on the P(VDF-TrFE)/PVP/PAMPS IPMNC can be utilized in various attractive applications such as energy harvesting, wearable electronics, humidity sensor, pulse, braille recognition, catalyst supports, bio-interfacing, and sensors.

Ion-exchange polymers modified bacterial cellulose electrodes for the selective removal of nitrite ions from tail water of dyeing wastewater

Ion-exchange polymer and modified carbonization bacterial cellulose (CBC) electrodes were fabricated using varying amounts of cation-exchange polymers (glutaric acid (GA) and sulfosuccinic acid (SSA)) and assembled within an asymmetric capacitive deionization unit (p-CDI). The performance of selective NO₂^- electro-adsorption was studied. The AC/CBC-SSA group showed a better salt adsorption capacity (14.56 mg/g) and nitrite removal efficiency (71.01%) than the AC/CBC-GA (10.72 mg/g, 47.83%) and AC/AC (4.81 mg/g, 12.74%) groups. It was confirmed that the CBC-SSA/GA electrodes enhanced nitrite selectivity and increased the adsorption capacity, and the total amounts of adsorbed anions increased when the applied voltage was increased from 0.8 to 1.2 V, while the molar fraction of nitrate decreased. The competitive and preferential adsorption of anions was further investigated using different binary solutions of anions and occurred in the following sequence: NO₂^- >SO₄^2- >NO₃^- >F^-≈ Cl^-. Furthermore, the p-CDI units were applied to remove nitrite in real wastewater samples, and the results showed that they had excellent reusability and application for use in dyeing wastewater treatment.

Porous polymers bearing functional quaternary ammonium salts as efficient solid catalysts for the fixation of CO2 into cyclic carbonates

A series of porous polymers bearing functional quaternary ammonium salts were solvothermally synthesized through the free radical copolymerization of divinylbenzene (DVB) and functionalized quaternary ammonium salts. The obtained polymers feature highly cross-linked matrices, large surface areas, and abundant halogen anions. These polymers were evaluated as heterogeneous catalysts for the synthesis of cyclic carbonates from epoxides and CO2 in the absence of co-catalysts and solvents. The results revealed that the synergistic effect between the functional hydroxyl groups and the halide anion Br(-) afforded excellent catalytic activity to cyclic carbonates. In addition, the catalyst can be easily recovered and reused for at least five cycles without significant loss in activity.