(573d) Assembly and Photoswitching Dynamics in Nanostructured Polymer Thin Films Revealed By Single-Molecule Super-Resolution Microscopy

Single-molecule super-resolution microscopy is attracting increasing attention in materials science by offering an exciting method for direct in situ real-space observation at nanometer resolutions. In this work, we develop a photoswitchable fluorophore optimized for organic environments, and we explore its incorporation into a super-resolution microscopy experiment. The fluorophore is polymerizable which greatly streamlines labeling strategies into a single step, where a small quantity is mixed with standard monomers and copolymerized to yield the functionalized material with no further purification. Individual fluorophores can be switched several times between bright and dark states, enabling repeated time-lapse imaging. We explore the photoswitching kinetics by comparing to Monte Carlo simulations, suggesting that the reaction dynamics are heterogeneous. In situ nanoscale imaging is demonstrated in solvent-swollen polymer blends, where coarsening behavior is readily observed. We hope our imaging platform promotes widespread adoption of super-resolution microscopy in the polymer community.