Probing polymer nanostructures with super-resolution fluorescence microscopy.

Super-resolution fluorescence microscopy (SRM) has emerged as a powerful tool for polymer characterization, providing nanometer-scale spatial resolution and molecular specificity. Recent advances in probe design, labeling strategies, and imaging methodologies have enabled SRM to move beyond structural visualization to chemical, mechanical, and dynamic characterization of polymer materials. This review summarizes the recent developments in SRM for polymer science from both methodological and application-oriented perspectives. We discuss fluorophore labeling strategies including covalent labeling, embedded probes, nanoparticle probes, and label-free approaches based on point accumulation for imaging in nanoscale topography (PAINT), as well as their advantages and limitations. Then, we highlight the applications of SRM in diverse polymer systems and functional measurements, including local chemical environments, domain selectivity, structural order, mechanical properties, molecular transport, and internal accessibility. Finally, the current challenges and future opportunities, including probe development, multimodal imaging, artificial intelligence-assisted analysis, and label-free imaging, are discussed. Continued advances in these areas are expected to establish SRM as a versatile characterization technique for investigating polymer structures and functions across multiple length scales.