Metal-Organic Framework superstructures with long-ranged orientational order via E-field assisted liquid crystal...

Area of Science:

• Materials Science
• Crystallography
• Nanotechnology

Background:

• Most metal-organic frameworks (MOFs) are non-cubic and prepared as microcrystalline powders.
• Their functionality often depends on crystallographic direction, necessitating methods for orientation and assembly.

Purpose of the Study:

• To develop a general method for orienting and assembling free-standing MOF crystals.
• To create highly oriented MOF superstructures with improved functionality.

Main Methods:

• Utilized electric-field assisted liquid crystal assembly.
• Applied the method to MIL-53-NH2(Al), MIL-68(In), and NU-1000 MOF crystals with varying aspect ratios.
• Photopolymerized the assembled MOF superstructures to fix their long-range order.

Main Results:

• Successfully formed highly oriented MOF superstructures.
• The method is applicable to polydispersed MOF crystals, overcoming limitations of traditional assembly techniques.
• Demonstrated applicability to MOFs with aspect ratios from 1.2 to 10.

Conclusions:

• Introduced a novel strategy for controlling MOF orientation and packing.
• This approach bypasses requirements for particle monodispersity, shape homogeneity, and high aspect ratios.
• Paves the way for developing advanced MOF composites with enhanced functionalities.