Hydrogen bond mediated load transfer in hybrid organic-inorganic materials
Steered molecular dynamics modeling pulling a PVA on a silicate substrate. The successive breakage and formation of H-bonds manifest a slip-steak behavior owing to the intrinsic brittle interface of PVA-silicate composites.
By combining platelet-like ceramic building blocks and organic matrices, nature creates hybrid materials such as bone, teeth and mollusk shells that have outstanding balance of stiffness, strength and flaw-tolerance. This has inspired fabrication of several advanced human-made polymer-matrix composites with inorganic reinforcing materials such as cement, clays, glass, graphite, SiC, and mica. However, the geometry and material property mismatch across the interface of hybrid materials make it extremely difficult to fully understand the lateral bonding processes and design composites with optimal mechanical performance. In this project, a combined first-principles calculations, molecular dynamics modeling and continuum derivations ar employed to unravel the detailed mechanisms of H-bonding, deformation, load transfer and failure at the interface of Polyvinyl alcohol (PVA) and silicates, as an example of hybrid materials with geometry and property mismatch across the interface. The goal is to establish a unified understanding to explain the interplay between geometric constraints, intra- and inter-molecular H-bonding, materials characteristics and optimal mechanical properties in hybrid materials. This fundamental approach is expected to provide de novo concepts, design principles and strategies to muddulate interfacial interactions and design hybrid composites with never-seen-before properties.