New Sulfonated Polystyrene and Styrene–Ethylene/Butylene–Styrene Block Copolymers for Applications in Electrodialysis

In this study we prepared blends of polystyrene (PS) and high-impact polystyrene (HIPS) with poly­(styrene–ethylene–butylene) (SEBS) triblock copolymer. After sulfonation, blends were used to fabricate ion-exchange membranes by solvent-casting and subsequent thermal treatment to obtain homogeneous packing densities. The morphology and structure of the blends were investigated by scanning electron microscopy, atomic force microscopy, and FTIR spectroscopy. Furthermore, the thermal transitions and stability of all the blends were characterized using calorimetric techniques and compared with those of the individual polymers. Analyses of the physical properties (i.e., ionic conductivity, ion-exchange capacity, water uptake, dimensional stability, mechanical properties, etc.) showed that the performance of the PS-containing membranes is, in general, higher than that of the HIPS containing one. Furthermore, the highest sulfonation degree was also found for the PS/SEBS membranes. The capabilities of the membranes were tested by investigating the extraction of Na⁺ by electrodyalisis. Comparison of the percentage of extracted ions indicates that the incorporation of SEBS results in a significant improvement with respect to membranes made of individual polymers

Flexible Electrodes for Supercapacitors Based on the Supramolecular Assembly of Biohydrogel and Conducting Polymer

Flexible and lightweight electrodes were prepared using a two-step process. First, poly­(3,4-ethylenedioxythiophene) (PEDOT) microparticles were loaded into poly-γ-glutamic acid (γ-PGA) hydrogel matrix during the reaction of the biopolymer chains with the cross-linker, cystamine. After this, PEDOT particles dispersed inside the hydrogel were used as polymerization nuclei for the chronoamperometric synthesis of poly­(hydroxymethyl-3,4-ethylenedioxythiophene) (PHMeDOT) in aqueous solution. After characterization of the resulting electrode composites, electrochemical studies revealed that the capacitive properties drastically depend on the polymerization time used to produce PHMeDOT inside the loaded hydrogel matrix. Specifically, flexible electrodes obtained using a polymerization time of 7 h exhibit an specific capacitance of 45.4 ± 0.7 mF/cm² from cyclic voltammetry and charge–discharge long-term stability. The applicability of these electrodes in lightweight and flexible energy-harvesting systems useful for energy-autonomous, low-power, disposable electronic devices has been proved powering a LED bulb