Nature harnesses the disorder of intrinsically disordered proteins to organize enzymes and biopolymers into membraneless organelles. The heterogeneous nature of synthetic random copolymers with charged, polar, and hydrophobic groups has been exploited to mimic intrinsically disordered proteins, forming complexes with enzymatically active proteins and delivering them into nonbiological environments. Here, the properties of polyelectrolyte complexes composed of two random copolymer polyelectrolytes are studied experimentally and via simulation with the aim of exploiting such complexes for segregating organic molecules from water. The anionic polyelectrolyte contains hydrophilic and hydrophobic side chains and forms self-assembled hydrophobic domains. The cationic polymer is a high-molecular-weight copolymer of hydrophilic and charged side groups and acts as a flocculant. We find that the polyelectrolyte complexes obtained with this anionic and cationic random copolymer system are capable of absorbing small cationic, anionic, and hydrophobic organic molecules, including perfluorooctanoic acid, a compound of great environmental and toxicologic concern. Importantly, these macroscopic complexes can be easily removed from water, thereby providing a simple approach for organic contaminant removal in aqueous media. MARTINI and coarse-grained molecular dynamics simulations explore how the microscale heterogeneity of these random copolymer complexes relates to their segregation functionality.

Effective control over the thermal behavior and mechanical strength of polymeric materials has been highly sought for decades and continues to this day, particularly with the urgent demand for highly durable energy storage devices and soft electronics, to name a few. Here, we report a simple yet versatile approach to fine-tune the glass transition range of a family of ionomers via their side-chain structure and charge fraction. We analyze ionomers of poly(3-sulfopropyl methacrylate-ran-methyl methacrylate) that are synthesized by conventional freeradical polymerization. Using derivative heat flow curves from differential scanning calorimetry, we find that above a critical low charge-carrying side-chain fraction (f q ), the glass transition temperature shifts to higher values and the glass transition breadth increases significantly in response to thermal treatment. After several thermal cycles, values of glass transition breadth as high as 90−104 °C were obtained, and the evolution from one glass transition regime to two distinct, contiguous glass transition regimes was evident. Quenched molecular dynamics simulations elucidate the roles of several key design parameters of the ionomers near the glass transition, specifically the importance of the charge-carrying polymer side chains. Analysis of energetics and structural relaxation dynamics reveals the effects of strong ionic correlations in a low dielectric constant medium and the side-chain mobility on the transition from liquid to supercooled liquid. As f q increases beyond a critical value and is accompanied by thermal treatment, the local ionic concentrations are more heterogeneous, and the distribution of the ionic cluster sizes becomes broader at the transition point. The resulting enhanced degree of compositional and dynamic heterogeneity leads to a shift in the supercooled liquid transition toward higher temperatures.