Novel sulfonated block copolymer containing pendant alkylsulfonic acids: Syntheses, unique morphologies, and applications in proton exchange membrane
(2325–2338)Journal of Polymer Science Part A: Polymer  Chemistry 49 #11 (2011)

Lee et al of National Taiwan University, Taiwan, synthesized poly(styrene-block-sulfonated hydroxystyrene) (PS-b-sPHS) with various compositions via anionic polymerization.  Proton exchange membranes (PEMs) were prepared from PS-b-sPHS with sulfonic acids in either potassium salts or tetra-alkylammonium salts via solvent casting and following treatments.  Some unique morphologies, such as hallow channels and lamellar arrangement of strings of beads, were observed as a consequence of equilibrium between microphase separation and columbic interactions between polyelectrolytes. The transportation properties were found to closely relate to the morphologies of the PEMs. The combination of microphase separation of block polyelectrolytes and freedom of movement of pendent alkylsulfonic acids was demonstrated to effectively enhance the proton transport and suppress the methanol crossover for the PEMs, leading to the selectivity higher than Nafion 117 by five times at most.  (RDC 4/22/2011)

Synthesis, characterization of novel silicotungstic acid incorporated SPEEK/PVA-co-ethylene-based composite membranes for fuel cell
(1741-1748) Journal of Materials Science 46 #6 (2011)
Ramaganthan, Sivakumar and Dharmalingam, India prepared sulfonated polyether ether ketone (SPEEK) is prepared by the sulfonation of polyether ether ketone (PEEK).  Among the five composite membranes, composite membrane with higher silicotungstic acid content, (which has 10% silicotungstic acid) showed more conductivity compared to other membranes. These composites also showed very good conductivities, mechanical properties, and durabilities. Hence, these composite membranes have the potential to be used in the development of newer proton exchange membrane fuel cells (PEMFCs). (RDC 2/22/2011)

2/4/2011
Sulfonated poly(bis-A)-sulfones as proton exchange membranes for direct methanol fuel cell application
(264–271)Polymer  Engineering &  Science 51 #2 (2011)
He eta, China prepared sulfonated poly(bis-A)-sulfone (SPSF) samples by a mild postsulfonation method using trimethylsilyl chlorosulfonate as sulfonation agent.  These SPSF membranes are thermally stable up to 450°C in air.  The hydrophilic ionic clusters become continuous to form channels when ion exchange capacity (IEC) reached 1.47 mequiv/g. Moreover, the membranes showed very good proton conductivities (20°C, 0.01–0.11 S/cm) and low-methanol permeability (0.09–3.06 × 10−6 cm2/s), and the methanol diffusion coefficients were lower than that of Nafion112 (1.35 × 10−6 cm2/s) with IEC values from 0.70 to 1.47 mequiv/g. However, the Fenton's reagent test revealed that the membranes exhibited very poor oxidation stability, which is the main defect limiting the application of SPSF for proton exchange membranes. (RDC 2/2/2011)