NAMS 2002 Workshop - ICOM 2008

Nanostructured Membranes I – 1 – Keynote
Monday July 14, 2:15 PM-3:00 PM, Moloka’i
Novel Polymers of Intrinsic Microporosity (PIMs): Towards An
Understanding of Structure-Property Relationships.
N. McKeown (Speaker), Cardiff University, Cardiff, UK, mckeownnb@cardiff.ac.uk
B. Ghanem, Cardiff University, Cardiff, UK
K. Msayib, Cardiff University, Cardiff, UK
P. Budd, Univesity of Manchester, Manchester, UK
D. Fritsch, GKSS, Germany
Polymers of Intrinsic Microporosity (PIMs) are materials that combine the
processability of polymers with a high degree of microporosity arising from their
rigid and non-planar structures that cannot fill space efficiently [1] . The rigidity is
enforced by the polymer backbone being composed solely of fused-rings and the
necessary sites of contortion are typically provided by spiro-centres or
triptycenes. PIMs can be prepared either as highly insoluble network polymers or
as soluble polymers (e.g. PIM-1, Fig. 1a and b) that are suitable for the
fabrication of self-standing films, submicron coatings or fibres a unique
advantage over conventional microporous materials. Their unique combination of
properties (microporosity, thermal stability, solubility and structural diversity)
makes them attractive for several applications [2] but they are particularly
promising as membrane materials. In particular, a number of published examples
of PIMs [3] display gas permeability data that lie above the Robeson plot [4] for the
separation of important gas pairs (e.g. O2/N2, CH4,CO2), showing that they have
good selectivity as well as high permeability. This presentation will describe
recent work at Cardiff that has the objective of preparing new PIMs to afford a
better understanding of polymer structure-property relationships. These PIMs are
derived from the chemical synthesis of novel monomers based on triptycenes,
spiro-bisindane and hexaazatrinaphthylene subunits, which are designed to
possess greater microporosity and/or binding sites for the inclusion of metals as
catalysts or for facilitated transport across the membrane. Attempts will be made
to correlate the structure of the PIM with the degree of microporosity achieved,
as assessed by low temperature gas adsorption, and their gas permeabilities.
[1] P. M. Budd, B. S. Ghanem, S. Makhseed, N. B. McKeown, K. J. Msayib, C. E. Tattershall,
Chemical Communications 2004, 230.
[2] A recent review on PIMs: N. B. McKeown, P. M. Budd, Chemical Society Reviews 2006, 35,
675.
[3] P. M. Budd, K. J. Msayib, C. E. Tattershall, B. S. Ghanem, K. J. Reynolds, N. B. McKeown, D.
Fritsch, Journal of Membrane Science 2005, 251, 263.