Optical Super-Resolution Imaging of Block Copolymer Thin Film Surface Morphology Using Fluorescent Silica Nanoparticles

Block copolymers (BCPs) are of tremendous academic and industrial interest, as they exhibit myriad tunable properties useful across a broad range of applications. This is particularly true for BCP thin films. Traditionally, imaging mesostructured BCP surfaces of such films has been dominated by electron and scanning probe microscopies. In recent years, however, high-resolution optical imaging in the far field has provided exciting opportunities for alternative approaches. Here, we report the optical super-resolution imaging of BCP thin film surface mesostructure through stochastic optical reconstruction microscopy (STORM). To that end, we introduce a new class of functionalized silica nanoparticles to enhance the brightness of encapsulated dyes for STORM, offering distinct advantages over conventional sample labeling with organic dyes. These nanoparticles are simply mixed with or attached to specific blocks of the BCPs, thereby enabling selective block staining and optical visualization. This allows for facile imaging of morphological features on the near-molecular scale, thus providing a versatile method for BCP surface morphology assessments using optical imaging.