Crystal Chemical Analysis Used to Predict the Mechanical Properties of Nanoporous Materials

The recognition of metal–organic frameworks (MOFs)
with
the 2025 Nobel Prize in Chemistry underscores the critical importance
of their porous and tunable architectures for applications like atmospheric
water harvesting, carbon dioxide capture, and toxic gas storage. Understanding
the mechanical properties of zeolites, open-framework aluminophosphates
(AlPOs), and MOFs porous materials is essential for predicting their
practical applications and synthesizability. By applying Alan L. Mackay’s
concept of “generalized crystallography,” we extend
principles from these microporous crystals to the design of 3D-printed
macroporous metamaterials and the derivation of universal, multiscale
patterns. We validate the relevance of this method by detecting correlations
between structural motifs and mechanical data for metamaterials consistent
with results from density functional theory (DFT) calculations for
crystals. The crystal chemical analysis involved simplifying crystal
structures into nets by constructing Voronoi–Dirichlet polyhedra
(VDP) using TOPOS or TopCryst in a fully automated mode. A strong
correlation between mechanical properties and the deviation of average,
maximum, and minimum bond angles from the regular angles of nets based
polyhedral was found. Pearson correlation analysis also showed that
greater distances between nodes in zeolites maximize their mechanical
properties. This means that SiO4 tetrahedra should join
as “straightforwardly” as possible, without any bends
that would reduce mechanical strength. For 3D-printed AlPOs, we observed
a strong negative Pearson correlation between mechanical properties
and the number of nodes and bonds, whereas for MOFs, the correlation
is positive. This suggests the existence of an optimal value for these
parameters to maximize mechanical properties at a given porosity.
The discovered regularities provide the fast screening of both the
most durable porous materials and 3D printed metamaterials.