Adsorption‐based separations have the potential to enhance the sustainability of established industrial processes and facilitate the adoption of new practices. They also provide ways to meet emerging needs in the isolation of resources from non‐traditional supplies and the remediation of hazardous environmental contaminants. In this regard, there are significant opportunities to advance both fundamental polymer science and engineering applications through next‐generation adsorbent systems. Here, after briefly reviewing the history, potential application space, and underlying physics of polymer sorbents, design considerations that connect macromolecular design with systems‐level functionality, are discussed. First, polymer processing conditions are discussed in terms of the final nano‐ and microscale structures produced. Subsequently, the macromolecular chemistry of the materials is analyzed with respect to the ability of the separations systems to have analyte‐specific binding. Finally, a similar analysis is performed regarding the desorption mechanism used to release the target solutes. In this way, the manuscript attempts to connect macromolecular architecture with polymer physics and materials processing to provide guidance on how these important interrelationships impact the ultimate performance of sorbent systems.

No abstract

Membranes based on microphase-separated copolymers offer an opportunity to address the need for resilient materials that can be used in organic solvent-based filtration. Specifically, copolymer repeat unit chemistries can be chosen to impart solvent compatibility, to tailor membrane nanostructure, and to enable postsynthetic modification. In this study, a poly(trifluoroethyl methacrylate-co-oligo(ethylene glycol) methyl ether methacrylateco-glycidyl methacrylate) [P(TFEMA-OEGMA-GMA)] copolymer was synthesized and fabricated into flat sheet and hollow fiber membranes using a non-solvent-induced phase separation casting technique. The GMA repeat units possess epoxide groups that were used to cross-link the copolymer through a ring-opening reaction with diamines ranging from diaminoethane to diaminooctane. Transport experiments in water, methanol, ethanol, tetrahydrofuran, dimethylformamide, and toluene demonstrated that films reacted with longer diamines, such as diaminohexane, result in stable membranes. Conversely, the films reacted with shorter diamines degraded upon exposure to organic solvents. Because of their stability in organic solvents, transport through the diaminohexane-functionalized membranes was characterized in more detail using hydraulic permeability and neutral solute rejection experiments. The results of these experiments along with volumetric swelling and small-angle X-ray scattering (SAXS) analysis revealed that the solvent affinity for the constituent copolymer domains is critical in determining the permeation pathway. For P(TFEMA-OEGMA-GMA) membranes in protic solvents, such as ethanol, transport through the hydrophilic side chains of OEGMA was favored, while for membranes in aprotic solvents, such as toluene, transport through the hydrophobic matrix dominated. In neutral solute rejection experiments, 2000 g mol −1 polypropylene glycol molecules (solvated size ∼2 nm) permeated through the hydrophobic domain unhindered but were fully rejected when permeation occurred through the hydrophilic region. These differences highlight the need to understand the interactions between the copolymer domains and solvent when solvent-resilient membranes are developed for organic solvent filtration.