Connection between Molecular Interactions and Mechanical Work of Adhesion.

Abstract

We correlate the strength of interfacial interactions with the adhesive force necessary to separate a polymer from a surface. It is intuitive that interactions would influence adhesion and friction; however, challenges in the direct measurement of the interaction strength at interfaces have obscured the connection between these interactions and such phenomena. We overcome this by using interface-sensitive sum frequency generation spectroscopy to determine the strength of interfacial interactions between polymers and sapphire through a shift in vibrational frequency and compare this with mechanical adhesion tests. Our results indicate that spectroscopic shifts can be used to directly estimate adhesion, especially for polar materials. This work provides a framework to connect molecular interactions to interfacial properties, enabling the design and rapid screening of molecular architectures.