A systematic study is presented that investigates the influence of the excluded volume effect by macromolecules on supramolecular polymerizations in organic media. Upon crowding, the discotic supramolecular monomers sequentially assemble into polymers and higher-order aggregates (HOAs), affected by the macromolecule's concentration, size and polarity. The proven tunability and general applicability of this entropically driven assembly open new avenues for applying macromolecular crowding beyond aqueous systems.

Abstract

Macromolecular crowding plays a crucial role in biological systems by regulating dynamic processes, yet its effects in fully synthetic environments remain largely unexplored. Here, we systematically investigate how excluded volume effects influence supramolecular polymerizations in organic media. We employ various discotic supramolecular monomers that assemble sequentially into polymers and kinetically-controlled higher-order aggregates (HOAs) only in the presence of macromolecular crowders. The phase diagram of the supramolecular assemblies reveals a strong dependence on the macromolecule concentration, size, and polarity, which can be tuned to control polymerization. Remarkably, at high crowder concentrations, large condensed and aligned assemblies were observed in dried samples, suggesting a transition to phase-separated states. By testing different monomers, macromolecules, and solvents, we establish the general applicability and versatility of macromolecular crowding in guiding supramolecular polymerization. This work provides fundamental insights into assembly processes in crowded environments and opens new avenues for applying macromolecular crowding beyond aqueous systems.