Low‐Symmetry MOF‐Based Patchy Colloids and Their Precise Linking via Site‐Selective Liquid Bridging to Form Supra‐Colloidal and Supra‐Framework Architectures

Abstract

Colloids with surface patches (or patchy particles) can bind and assemble with directionality. However, the bonding between the usually high-symmetry, dome-shaped patches is not precise, as it cannot lock the exact position and orientation of the relevant particles. This issue prevents the assembly of well-defined colloidal superstructures by design. Herein, we introduce low-symmetry, metal-organic framework (MOF)-based patchy colloids, which feature a polyhedral matrix and flat hexagonal patches, along with anisotropic surfaces and compositions. Guided by the encoded shape/ chemical information and mediated by a site-selective liquidbridging interaction, the distinct patchy particles self-assemble into supra-colloidal (or supra-framework) structures with unprecedented precision. In this case, the valence, position, and orientation of the particles within assemblies are fully coordinated and precisely aligned. The dynamic nature of the liquid bridges also allows us to investigate the unique assembly kinetics. Our strategy not only defines new modes of colloidal bonding, but also provides a powerful means toward creating hierarchical and multi-component MOF materials.

Low-dimensional assemblies of metal-organic framework particles and mutually coordinated anisotropy

“…Despite the enormous potentials, harnessing the rich and unique information encoded in diverse MOF systems (with regards to their diverse types, shapes, sizes, and functions) and expressing them into new colloidal structures and functional properties remain limited. So far, several approaches have been explored to assemble MOF particles, using capillary force 16 – 18 , DNA hybridization 19 , polymer matrix 20 , electric field 21 , and more recently liquid bridging 22 . Although assemblies have been achieved, these methods either require extensive surface functionalization, focus on densely packed nanometer-sized particles, or produce imperfectly aligned structures.…”

Recent advances in nanoarchitectures of monocrystalline coordination polymers through confined assembly

“…The specific site of the coordination polymer crystals could be modified to generate patchy colloids. By selectively growing a thin layer of UiO-66 on two facets of MIL-96 microcrystals, patchy colloidal particles could be synthesized [ 135 ]. The UiO-66 parts show an affinity to oligomers of 3-(trimethoxysilyl)propyl methacrylate ( o -TPM).…”

Solvent-induced assembly of mono- and divalent silica nanoparticles

“…Colloidal chains have been obtained by the assembly of Janus particles with one face selectively functionalized with DNA containing a self-complementary sticky end [ 19 ], particles with two patches functionalized with metal-coordination-based recognition units [ 20 ], and by co-assembly of block copolymer micelles and hard nanoparticles [ 21 ]. Particles with two patches located at opposite poles have been assembled into a Kagome lattice by hydrophobic interactions [ 22 ], into chains by liquid bridging [ 23 ], and into a series of structures under an AC electric field [ 24 ]. The linear self-assembly of patchy gold nanorods tethered with hydrophobic polymer chains at both ends can be triggered by solvophobic attractions induced by a change in solvent quality [ 25 ].…”