Dual electrospray-assisted forced blending of thermodynamically immiscible polyelectrolyte mixtures

Polyelectrolytes have garnered significant attention as a key electrochemically-active component in a diversity of energy-related industry fields. Among enormous efforts to develop advanced polyelectrolytes, blending of different polyelectrolyte mixtures is suggested as a facile and efficient way. However, unavoidable thermodynamic immiscibility between the blend components has often caused serious challenges in the versatile fabrication of polyelectrolyte blends with desirable membrane properties. Here, as an unprecedented mixing strategy to address this issue, we demonstrate a new class of dual electrospray (DES)-assisted forced polymer blending. As a model system to explore the feasibility of this blending approach, Nafion and multiblock sulfonated hydrocarbon copolymer (denoted as sBlock) comprising sulfonated hydrophilic poly(arylene thioether sulfone) blocks and hydrophobic poly(arylene ether sulfone) blocks are chosen. The processing uniqueness and simplicity of the DES blending technique enable the successful fabrication of Nafion/sBlock blends (referred to as N/B blends) that are difficult to achieve with conventional blending methods due to their large miscibility difference. More notably, during the DES blending, nonsolvent-induced nanophase morphology reconstruction occurs in the N/B Blend, eventually giving rise to some difference in proton conductivity between experimental values and theoretically predicted ones. We envision that the DES-assisted forced blending strategy holds a great deal of promise as a versatile and scalable manufacturing technology to breakthrough the deadlock of thermodynamically immiscible polymer blends and also can be easily applicable to a wide variety of polymer blend systems.