Inside membranes: unveiling chain conformation in poly(butylene oxide)-block-polyglycidol polymersomes

Polyglycidol-based polymersomes are promising scaffolds for artificial organelles, yet the structural principles governing their assembly remain poorly understood. Here, we report the synthesis of well-defined amphiphilic linear block copolymers via anionic ring-opening polymerization and further probed their self-assembly in aqueous media. Systematic variation of formulation parameters, combined with statistical analysis, reveals clear relationships between the resulting morphologies and key molecular descriptors, including the polyglycidol weight fraction (w_PGL) and the degree of polymerization of the hydrophobic block (X_n-PBO). Membrane thickness scales with hydrophobic block length, whereas increasing w_PGL notably influences vesicular organization. The polyglycidol block enforces a greater stretching penalty on the hydrophobic PBO segment than is typically observed in poly(ethylene oxide)-based systems, thus producing distinct membrane features. The copolymer architecture was evidenced to play a role on the stretching of the hydrophobic membrane, with triblock copolymers extending more the hydrophobic blocks than diblock copolymers. Together, these results clarify the mechanisms governing membrane formation in polyglycidol-containing assemblies and establish these polymersomes as a versatile platform for biomimetic compartmentalization.