Deformation Behavior of Glass Nanostructures in Hot Embossing

In the nanoscale glass formation, the flow and deformation behavior of glass materials are quite different from those in the macroscale because the mold cavity influences the viscous flow behaviors of glass because of the size effect. The knowledge of macroglass molding process no longer applies to the fabrication of glass microparts by hot embossing. To investigate the size effect of the mold cavity on glass flow behavior during squeeze flow, patterned molds with different length scales and shapes were used for glass embossing. The experimental results demonstrated that glass structures with ultrafine and atomic scale surface could be fabricated by using precision embossing. The nanostructures of embossed glass at 100 and 500 nm wide cavity were found to exhibit nanoscale effect during squeeze flow. Molecular confinement accelerates the tectonic deformation of embossed glass at smaller length scales. At the microscale filling, the tectonic deformation of embossed glass is mainly dominated by elastic recovery, surface tension, hydrostatic pressure, and viscous flow. As the length scale reduces to submicron, the dual-peak filling mode gradually transfers to the single-peak filling mode. Additionally, deformation modes have little influence on the shapes of the mold cavity. This work sheds light on the fabrication of glass nano/microstructures.