Soft Matter, 2019, vol 15, 26, pp. 5193-5203
DOI:10.1039/C9SM00484J
Abstract
The combination of precision control with wide tunability remains a challenge for the fabrication of porous nanomaterials suitable for studies of nanostructurebehavior relationships. Polymer micelle templates broadly enable porous materials, however micelle equilibration hampers independent pore and wall size control. Persistent micelle templates (PMT) have emerged as a kinetic controlled platform that uniquely decouples the control of pore and wall dimensions. Here, chain exchange is inhibited to preserve a constant template dimension (pore size) despite the shifting equilibrium while materials are added between micelles. Early PMT demonstrations were synthesis intensive with limited 11.3× pore size tuning for a given polymer. Here we demonstrate PMT swelling with homopolymer enables 13.2× (13.341.9 nm) pore size variation while maintaining a monomodal distribution with up to 250 wt% homopolymer, considerably higher than the ?90 wt% limit found for equilibrating micelles. These swollen PMTs enabled nanomaterial series with constant pore size and precision varied wall-thickness. Kinetic size control here is unexpected since the homopolymer undergoes dynamic exchange between micelles. The solvent selection influenced the time window before homopolymer phase separation, highlighting the importance of considering homopolymersolvent interactions. This is the first PMT demonstration with wide variation of both the pore and wall dimensions using a single block polymer. Lastly this approach was extended to a 72 kg mol?1 block polymer to enable a wide 50290 nm range of tunable macropores. Here the use of just two different block polymers and one homopolymer enabled wide ranging pore sizes spanning from 13.3290 nm (122×).
