280519 Nanostructured Block Copolymer Membranes for Biofuel Production

Tuesday, October 30, 2012: 3:15 PM
Butler West (Westin )
A. Evren Ozcam, University California, Berkeley, Berkeley, CA, Ashish Jha, Chemical and Biomolecular Engineering, University California, Berkeley, Berkeley, CA and Nitash P Balsara, Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, CA

We report on the effect of changing nanoscale morphology on pervaporation of alcohol/water mixtures through block copolymer membranes.  Experiments were conducted using polystyrene-b-polybutadiene-b-polystyrene (SBS) and polystyrene-b-polydimethylsiloxane-b-polystyrene copolymers with polybutadiene (PB) and polydimethylsiloxane (PDMS) as the alcohol transporting blocks.  The morphology of the membranes is governed by the composition of the block copolymer while the size of the domains is governed by the molecular weight of the block copolymer.  The volume fraction of the transporting PB and PDMS microphases was varied from 0.63 to 0.93 and 0.59 to 0.83 for PB (fPB) and PDMS (fPDMS) microphases, respectively.  The overall molecular weight of the copolymers, Mn, was varied from 34 to 207 kg mol-1.  Normalized ethanol permeability through the membrane, PE /fPB  , and the ethanol selectivity, aEW, increase with increasing Mn for SBS, but PE /fPDMS  and aEW are not a strong function of Mn for SDS based membranes. Master curves are obtained when all of the permeation data are plotted in the PE /ftransporting, PW/ftransporting, versus aEW format. 

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See more of this Session: Diffusion in Polymers
See more of this Group/Topical: Materials Engineering and Sciences Division