Polyionic liquid Nanolayers

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Poly(ionic liquid) Nanolayers
Scott M. Husson, Department of Chemical and
Biomolecular Engineering, Clemson University
Polymerized ionic liquids have excellent thermal
resistance, high CO2 sorption capacities at low
pressure, fast reversible adsorption/desorption,
and exceptional selectivity for CO2 over
permanent gases. These properties make pILs
outstanding candidates as membrane separation
layers for selective CO2 recovery from gas
mixtures that are generated by combustion of
fossil fuels. Our approach uses
surface-initiated atom transfer radical
polymerization to produce highly uniform pIL
nanolayers with controllable graft densities and
independently controllable thicknesses. We have
exploited this flexibility and control to
systematically study how nanolayer structure, in
addition to chemistry, affects CO2 sorption. One
result is shown below that illustrates how
grafting a pIL nanolayer from a membrane support
transforms it into a CO2 selective barrier. We
also have measured CO2 adsorption isotherms for
grafted pILs that vary in layer thickness and pIL
anion (BF4-, CH3SO3-, CF3SO3-).
Membrane support allows non-selective transport
of CO2 and N2.
Membrane support coated with pIL nanolayer
transports CO2 selectively over N2.