Block Composition Dictates Infiltration Kinetics of Block Copolymers into Nanopores

Polymer infiltration and reorganization under nanoscale confinement provide critical insights into the molecular processes governing nanocomposite formation, interfacial assembly, and selective transport. Here, we systematically investigate the infiltration behavior of poly(styrene-b-2-vinylpyridine) (PS-b-P2VP) block copolymers (BCPs) with varying block fractions into silica nanoparticle packings using in situ spectroscopic ellipsometry. Below the order–disorder transition temperature, the BCPs infiltrate while retaining their microphase-separated morphology. Within this ordered regime, the BCPs infiltrate more slowly than the homopolymers due to structural constraints imposed by microphase ordering. At the same time, increasing the P2VP fraction substantially accelerates infiltration kinetics owing to the strong interfacial affinity between P2VP and silica. These findings demonstrate that polymer block composition governs infiltration kinetics under nanoscale confinement, providing a molecular framework for designing structured nanocomposites and selective membranes.