Surface premelting and melting of colloidal glasses

The nature of liquid-to-glass transition is a major puzzle in science. A similar challenge exists in glass-to-liquid transition, i.e., glass melting, especially for the poorly investigated surface effects. Here, we assemble colloidal glasses by vapor deposition and melt them by tuning particle attractions. The structural and dynamic param-eters saturate at different depths, which define a surface liquid layer and an intermediate glassy layer. The power-law growth of both layers and melting front behaviors at different heating rates are similar to crystal premelting and melting, suggesting that premelting and melting can be generalized to amorphous solids. The measured single-particle kinetics reveal various features and confirm theoretical predictions for glass surface layer.

Automated summary

The nature of liquid-to-glass transition and glass-to-liquid transition is investigated in this study, especially focusing on the surface effects. Colloidal glasses are assembled by vapor deposition and melted by adjusting particle attractions. The results show the presence of a surface liquid layer and an intermediate glassy layer, and similar melting behaviors to crystal premelting and melting. Single-particle kinetics measurements confirm theoretical predictions for the glass surface layer.