Toughness Governs the Rupture of the Interfacial H‑Bond
Assemblies at a Critical Length Scale in Hybrid Materials
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Abstract
The geometry and material property
mismatch across the interface
of hybrid materials with dissimilar building blocks make it extremely
difficult to fully understand the lateral chemical bonding processes
and design nanocomposites with optimal performance. Here, we report
a combined first-principles study, molecular dynamics modeling, and
theoretical derivations 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. We identify contributing
H-bonds that are key to adhesion and demonstrate a specific periodic
pattern of interfacial H-bond network dictated by the interface mismatch
and intramolecular H-bonding. We find that the maximum toughness,
incorporating both intra- and interlayer strain energy contributions,
govern the existence of optimum overlap length and thus the rupture
of interfacial (interlayer) H-bond assemblies in natural and synthetic
hybrid materials. This universally valid result is in contrast to
the previous reports that correlate shear strength with rupture of
H-bonds assemblies at a finite overlap length. Overall, this work
establishes a unified understanding to explain the interplay between
geometric constraints, interfacial H-bonding, materials characteristics,
and optimal mechanical properties in hybrid organic–inorganic
materials