Low-Angle Rotational Interferometric Scattering Microscopy Enables Real-Time, Deep-Field Visualization of Stress-Driven Nanowire Oxidation Dynamics

Real-time visualization of nanoscale chemical transformations is critical to understanding morphological dynamics that influence catalytic and material properties; however, conventional optical methods remain limited by shallow penetration depths and persistent imaging artifacts. Here, we present low-angle rotational interferometric scattering microscopy (LRISM), a label-free imaging approach that achieves artifact-free, high-contrast imaging with high depths (>6 μm) into bulk solutions. By rapidly modulating the azimuthal angle of illumination, LRISM eliminates interference artifacts and extends imaging depth into the bulk solution. Using LRISM, we investigated the oxidation dynamics of individual silver nanowires in ferric chloride solutions, revealing distinct concentration-dependent morphological transformations: stress-induced bending driven by uneven silver chloride (AgCl) deposition, or nearly complete dissolution under conditions favoring AgCl solubilization. Further demonstrating LRISM's versatility and deep-imaging capabilities, we explored complex interfacial dynamics of electrochemically generated bubbles during the hydrogen evolution reaction on platinum electrodes, identifying and differentiating surface-attached and bulk-generated bubbles simultaneously. LRISM provides an accessible tool for the real-time observation and precise manipulation of nanomaterial shape, with broad implications for catalysis, semiconductor devices, and nanoscale material engineering.