Structural optimization of model sample for high-resolution soft/hard interface analysis

High-resolution structural analysis of adhesive interfaces between resins (soft materials) and inorganic materials (hard materials) is indispensable for understanding the underlying adhesion mechanisms. Scanning transmission electron microscopy-based electron energy-loss spectroscopy (STEM-EELS) is a key technique for obtaining information regarding the local chemical environment at the interfaces between amorphous resins and inorganic materials, such as metals. For realizing high-resolution STEM-EELS analysis, the design of the soft/hard interface model must be optimized. Furthermore, damage to resins caused by ion-beam irradiation during the sample milling must be avoided. Herein, we report an optimized protocol for fabricating specimens of soft/hard interfaces with ultrathin cross-sections for STEM-EELS analysis.