Homogeneous films with tailored microporous structures are crucial for
several applications, yet fabricating such films presents significant
challenges. This is primarily because most microporous materials have
crystal sizes in the nano- and micrometer ranges, which inevitably
generates intergranular spaces in the films, thereby complicating the
fabrication of these thin films. We used functionalized metal-organic
polyhedra (MOPs) as discrete microporous units and assembled them into
homogenous microporous films. This study focused on avoiding the
generation of intergranular spaces while controlling packing parameters
and film thicknesses. Initially, the MOP units, influenced by van der
Waals forces between the functionalized acyl carbon chains, displayed an
affinity to form spindle-shaped blocks and islands. As the MOP
concentration increased, these structures self-assembled into a
hexagonally packed structure with an in-plane orientation and a maximum
stacking of two layers of MOPs. By contrast, un-functionalized MOPs
yielded a disordered film structure formed by random agglomeration.
Evidently, functionalized adipoyl chloride influences the orientation of
the MOP network films with uniformly distributed micropores, effectively
preventing the formation of intergranular spaces. Additionally,
formaldehyde adsorption and desorption experiments revealed that the MOP
network films possess superior adsorption and desorption capacities. The
proposed approach signifies a breakthrough in the fabrication of
homogenous microporous films.