A fast, inexpensive, room-temperature process developed by an Australian-Japanese collaboration will enable scientists to pursue industrial exploitation of an ultraporous material with great potential for sensing, microelectronics, biomedics, optics and catalysis applications.

Metal-organic framework (MOF) materials are porous materials with tuneable architecture and chemical composition.[1]  MOFs can contain as much 80-90% empty space, enabling them to hold amazing amounts of gases such as hydrogen, methane and carbon dioxide. Their unique properties also make them potentially suitable for advanced applications such as miniaturised multifunctional devices.[2]  A key challenge is to position the MOFs precisely and accurately.

CSIRO researchers in an Australian-Japanese collaboration with Osaka Prefecture University used the Synchrotron to assist the development of a fast, inexpensive, room-temperature process for coating a particular kind of MOF onto copper metal plates, 3D objects and meshes.[3]

The two-step process, which takes less than an hour at room temperature, can be applied to any copper metal object. The first step involves growing copper hydroxide nanotubes on copper metal. The second step converts the copper hydroxide nanotubes into a more uniform coating of MOF crystals that covers the copper surface while maintaining the shape of the original metallic object.

The MOF coatings can be readily patterned using sunlight, making it ideal for exploring industrial applications of MOF capabilities.

The researchers used small angle x-ray scattering (SAXS) at the Synchrotron to confirm that the MOF structure produced by their new process was identical to the MOF structure produced by more conventional processes.

Kenji Okada et al., Copper Conversion into Cu(OH)2 Nanotubes for Positioning Cu3(BTC)2 MOF Crystals: Controlling the Growth on Flat Plates, 3D Architectures, and as Patterns, Adv. Funct. Mater., 24, 1969–1977 (2014) http://onlinelibrary.wiley.com/doi/10.1002/adfm.201470087/abstract

Image is copyright Wiley-VCH Verlag GmbH & Co. KGaA. Reproduced with permission.

The researchers acknowledge support schemes for the current research:  Australia-Japan ERLEP administrated by ATSE-EAJ-JSPS, Australian Research Council (ARC, DECRA Grant DE120102451), CSIRO AMTCP and OCE science team, Grant-in-Aid from the Ministry of Education, Culture, Sports, Science and Technology (MEXT), administered by Japan Society for the Promotion of Science (JSPS) (No. 22360276, No. 2510817).

References

[1] C.M. Doherty et al., “Using Functional Nano- and Micro-particles for the preparation of Metal Organic Framework Composites with novel properties” Accounts of Chemical Research 2014 47(20) 396–405 http://pubs.acs.org/doi/abs/10.1021/ar400130a
[2] P. Falcaro et al., “MOF positioning technology and device fabrication”, Chem.Soc.Rev. 2014, 43 (16), 5513-5560. http://pubs.rsc.org/en/content/articlehtml/2014/cs/c4cs00089g
[3] K. Okada et al., “Copper conversion into Cu(OH)2 nanotubes for positioning Cu3(BTC)2 MOF crystals: controlling the growth on flat plates, 3D architectures and as patterns” Advanced Functional Materials 2014, 24(14), 1969–1977