Synthesis and Structure-Conductivity Relationship of Polystyrene-block-Poly(vinyl benzyl trimethylammonium) for Alkaline Anion Exchange Membrane Fuel Cells
Abstract
Block copolymers of polystyrene-b-poly(vinyl benzyl trimethylammonium tetrafluoroborate) (PS-b-[PVBTMA][BF4]) were synthesized by sequential monomer addition using atom transfer radical polymerization. Membranes of the block copolymers were prepared by drop casting from dimethylformamide. Initial evaluation of the microphase separation in these PS-b-[PVBTMA][BF4] materials via SAXS revealed the formation of spherical, cylindrical, and lamellar morphologies. Block copolymers of polystyrene-b-poly(vinyl benzyl trimethylammonium hydroxide) (PS-b-[PVBTMA][OH]) were prepared as polymeric alkaline anion exchange membranes materials by ion exchange from PS-b-[PVBTMA][BF(sub 4)] with hydroxide in order to investigate the relationship between morphology and ionic conductivity. Studies of humidity [relative humidity (RH)]- dependent conductivity at 80 deg C showed that the conductivity increases with increasing humidity. Moreover, the investigation of the temperature-dependent conductivity at RH = 50, 70, and 90% showed a significant effect of grain boundaries in the membranes against the formation of continuous conductive channels, which is an important requirement for achieving high ion conductivity.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 2012
- Accession Number
- ADA581390
Entities
People
- Andrew M Herring
- Ashley M. Maes
- Craig Versek
- E. Bryan Coughlin
- Mark Tuominen
- Matthew W Liberatore
- Melissa A. Vandiver
- Soenke Seifert
- Tsung-han Tsai
Organizations
- Argonne National Laboratory