Self-Assembled Metal Organic Frameworks
Metal-organic Frameworks (MOFs) are nanoporous materials which have tunable physical and chemical properties which can have multiple functions. They are highly-ordered, hierarchical structures which can extent over large areas and have a very high surface area to volume ratio. Oxford researchers have developed a process to deposit tunable thin films of MOFs at room temperature and pressure, which opens up a vast array of potential applications in electronics, optoelectronics, sensors, gas storage and delivery, phase separation and catalysis.
Metal-Organic Frameworks (MOFs) are multifunctional hybrid (inorganic-organic) materials with 3-dimensional extended architectures and are constructed from repeating symmetric units through the self-assembly of molecular building blocks. MOFs are formed of metal ions to which organic ligands attach and extend to other ligand molecules. MOFs can be designed to produce a variety of functional crystalline materials by employing a multitude of coordinating organic linkers and metal ions, thereby resulting in numerous chemical and physical properties. MOFs have a 3D crystalline, nanoporous architecture with an extremely large internal surface area, typically >> 1,000 m2/g.
Up until now, synthesis techniques such as hydrothermal or solvothermal reactions could take up to a week to complete without control over the MOF particle size, whilst self-assembly of monolayers is far too costly and not scalable. Also, MOFs have limited electrical conductivity due to poor electron delocalisation and grain boundaries.
A new approach
Oxford researchers have developed a class of MOFs and have patented the straightforward technology to make them with a number of advantages over contemporary MOFs:
- They have tunable, multifunctional physical and chemical properties,
- They show unique reversible responses against thermal, mechanical and chemical stimuli,
- They can transform into visco-elastic hybrid materials and can be shaped quite easily,
- They have highly-aligned hierarchical microstructures with evenly spread MOF nanoparticles,
- They can be synthesised rapidly and in bulk quantities at room temperature and pressure,
- They can self-assemble into large-area thin films using a sol-gel process to yield controlled thicknesses.
MOF thin films, nanoparticles, nanocomposites and hybrid gels have the potential to be applied to a wide range of commercial applications including:
- Rapid multi-responsive and multi-stimuli smart sensors, for example in the reversible detection of volatile organic compounds,
- Micro- and nanosized interconnects for integration into MEMS and NEMS devices and high-response tunable resonators,
- New electrolytes for energy conversion and storage devices such as rechargeable batteries, proton conducting membranes and fuel cells,
- Large-area thin film generation for use in energy harvesting applications such as photovoltaics and photocatalysis,
- Ultra low-k dielectrics for use by next-generation supercapacitors,
- Bespoke lighting and electroluminescence,
- Drug delivery and gene therapy by using biodegradable MOFs as the vehicle and trigger.
The fabrication process is the subject of a patent application which will expand in due course. Further refinements and development of the technology are continuing under a number of applied research programmes.
We are actively looking for commercial partners to develop new devices based on this technology.
about this technology