Surface-Resolved Mapping of Structural Disorder in Colloidal Glass-Forming Analogues.

Understanding the microscopic origins of glass formation remains a fundamental challenge in the field of physical chemistry. Despite extensive studies, direct structural indicators that predict glass-forming ability (GFA) are still lacking. Here, we introduce a binary colloidal model system that provides real-space composition-resolved visualization of structural disorder. Bidisperse polystyrene particles, assembled under near-equilibrium conditions, replicate the size ratio of Cu-Zr metallic glasses, an archetypal system with a broad GFA window and well-established structure-property correlations. Two-dimensional image analyses reveal distinct disorder signatures (enhanced five- and seven-sided coordination, damped spatial correlations, and irregular hexagonal packing) converging within the range of 21.54-66.67 atom % Zr analogue, consistent with known GFA in atomic systems. These structural features correlate with enhanced mechanical strength and optical uniformity, demonstrating a clear structure-function relationship. This chemically tunable, geometrically governed platform offers an interpretable and data-rich approach for probing the physical basis of amorphous stability, advancing predictive modeling of disorder-property relationships in glass-forming materials.