NAMS 2002 Workshop - ICOM 2008

Gas Separation I – 4
Monday July 14, 11:15 AM-11:45 AM, Kaua’i
Gas Separation Using Ionic Liquid Polymers
R. Noble (Speaker), University of Colorado, Boulder, CO, USA, nobler@colorado.edu
D. Gin, University of Colorado, Boulder, CO, USA
J. Bara, University of Colorado, Boulder, CO, USA
T. Carlisle, University of Colorado, Boulder, CO, USA
B. Voss, University of Colorado, Boulder, CO, USA
A. Finotello, University of Colorado, Boulder, CO, USA
The objectives of this research are to fabricate new membrane structures based
on polymerizable ionic liquids; and characterize their fundamental gas and vapor
transport properties. Room temperature ionic liquids (RTILs) with polymerizable
groups can be readily converted into solid-state, poly(RTILs) for use as gas
separation membranes. The membranes will be fabricated from ILs (which will
act as the active component to provide high selectivity for the target agents) and
polymerizable ILs (which can be formed directly into solid, mechanically stable
and tunable polymeric solids). The use of polymerizable lyotropic liquid crystals
(LLCs) as a blendable additive to these IL materials provides a means to obtain
specific nanoporous morphologies that provide the potential for enhanced
sorption capacity in the resulting films or particles. LLC systems have the ability
to form ordered, phase-segregated nanoporous structures and incorporate the IL
into the ordered hydrophilic regions to generate very high surface area materials.
Separately, the addition of inorganic NPs to IL-based sorbent systems will allow
formation of solid-state materials, and provide additional surface area and
adsorption capacity for the target agents. Regular solution theory has been
shown to accurately predict the solubility of various gases and vapors in ionic
liquids and polymers. The IL solubility parameter can be tailored to minimize the
difference between the target agent and IL solubility parameters which
maximizes the solubility. A functional group contribution method to determine the
solubility parameter can be used to guide the detailed molecular design of the
ionic liquid. This method provides a theoretical framework to interface with the
material synthesis and characterization. Polymerizable ILs have already been
shown to have properties that exceed the upper bound on a Robeson plot for
CO2/N2 separation. The use of various additives can further enhance the
permeation while maintaining the high selectivity. Results will be shown for a
variety of materials.