Binding crystalline solids at low temperatures

Binding crystalline solids at low temperatures

Chen, Z.
Xu, Z.
Wang, G.
Li, H.
Chen, B.
Zeng, X.C.
Tan, L.

2013-06-16

Crystalline solids are solid materials whose constituent atoms, molecules, or ions are arranged in a highly regulated fashion. Due to lack of rotational freedom in their stacking, they have been known as fragile materials. Even though some efforts have been dedicated to bind or mend defects/cracks in amorphous materials like concrete or polymers, welding or binding a crystalline solid at ambient or low temperature conditions is quite a challenging task. Mainly, low interface mobility from the atomic or ionic constituents frequently limits interface regroupings. We recently found that one type of crystalline solid, dubbed metal-organic frameworks (MOFs), shows interfacial binding capability in their solid state. MOFs are molecularly engineered crystals that are mechanically rigid but structurally dynamic and reconfigurable. Unlike traditional studies on surface area and porous structures, our particular interest is placed on surface repairing or regrouping activities. For instance, when defects on bulk MOFs are mended using our process, the solids show a modulus leap from 4 to 12 GPa and hardness from 400 to 1000 MPa. When solids are made as polymer composite, open wounds can be healed at ambient conditions. Moreover, we found that low temperatures down to -56 ºC did not appear to restrict this solid binding process, making it outstanding for low temperature healing or binding. If our results are utilized for many other MOFs that are adopted as catalysts or hydrogen storage/separation materials, we expect their structure integrity can be kept after multiple cycles of packing or extensive uses. Furthermore, the knowledge gained will help people design future crystalline solids or ordered structures that can be assembled, repaired or healed in various engineering applications.

supramolecules
crystalline solids
metal-organic frameworks
self-healing

http://resolver.tudelft.nl/uuid:f10debd8-2f20-4710-b9cb-df3c710db23b

Conference proceedings

conference paper

(c) 2013 Chen, Z.; Xu, Z.; Wang, G.; Li, H.; Chen, B.; Zeng, X.C.; Tan, L.