PIM-1/graphene mixed matrix membranes

The award of the 2010 Nobel Prize in Physics to Andre Geim and Kostya Novoselov at the University of Manchester focused attention on the unique properties of graphene. A little before the groundbreaking experiments in graphene were reported in 2004,1 the first membrane-forming Polymer of Intrinsic Microporosity (PIM), commonly referred to as PIM-1, was synthesised in Manchester.2, 3 It is natural to bring these two developments together, in the form of PIM-1/graphene mixed matrix membranes. Graphene has many unusual properties, but of particular interest here is its barrier performance (a perfect graphene sheet is impermeable even to helium) and its high surface area, which is the basis of many traditional uses of carbons. PIMs have macromolecular structures designed to create internal surface area, comprising fused ring sequences (analogous to graphene) interrupted by spiro-centres. PIM-1 membranes are of interest for organophilic liquid separations3, 4 as well as gas and vapour separations.5, 6 In gas separation, PIM-1 was shown to surpass the 1991 Robeson upper bound7 for certain gas pairs, and contributed to the 2008 revision of the upper bound.8 The incorporation of graphene flakes into PIM-1 has the potential to modify the performance in various ways. Depending on the size, shape, distribution and concentration of the flakes, and their interactions with the polymer, permeability may be reduced through blockage of diffusion pathways, or enhanced through the creation of additional surface area and disruption to polymer packing. In addition to its effect on transport properties, the addition of graphene may modify the mechanical behaviour and, in particular, help to control the effects of physical ageing. PIM-1/graphene mixed matrix membranes are being investigated for both liquid and gas separations. Preliminary experimental and computational results will be presented. References 1.K. S. Novoselov, A. K. Geim, S. V. Morozov, D. Jiang, Y. Zhang, S. V. Dubonos, I. V. Grigorieva and A. A. Firsov, Science 306, 666 (2004). 2.P. M. Budd, B. S. Ghanem, S. Makhseed, N. B. McKeown, K. J. Msayib and C. E. Tattershall, Chem. Commun., 230 (2004). 3.P. M. Budd, E. S. Elabas, B. S. Ghanem, S. Makhseed, N. B. McKeown, K. J. Msayib, C. E. Tattershall and D. Wang, Adv. Mater. 16, 456 (2004). 4.S. Tsarkov, V. Khotimskiy, P. M. Budd, V. Volkov, J. Kukushkina and A. Volkov, J. Membr. Sci. 423-424, 65 (2012). 5.P. M. Budd, K. J. Msayib, C. E. Tattershall, B. S. Ghanem, K. J. Reynolds, N. B. McKeown and D. Fritsch, J. Membr. Sci. 251, 263 (2005). 6.P. M. Budd, N. B. McKeown, B. S. Ghanem, K. J. Msayib, D. Fritsch, L. Starannikova, N. Belov, O. Sanfirova, Y. Yampolskii and V. Shantarovich, J. Membr. Sci. 325, 851 (2008). 7.L. M. Robeson, J. Memb. Sci. 62, 165 (1991). 8.L. M. Robeson, J. Membr. Sci. 320, 390 (2008).