layered silicate, layer-by-layer self-assembly, DMFC, Nafion, methanol crossover
Layered silicates currently find uses in ion-exchange, adsorption, catalysis and fabrication of nanocomposites. Several layered silicates have channel systems or open frameworks within layers. They can be used to solve the problem for direct methanol fuel cells (DMFCs). In order to block the methanol crossover through Nafion, selective multilayer formation on the surface of Nafion by layer-by-layer self-assembly with permselective layered silicate (AMH-3). AMH-3 has three-dimensional microporous layers containing eight-membered rings opening. AMH-3 can be used as selective permeable barrier for DMFCs because of its pore size has smaller than diameter of methanol, and bigger than that of water, its three-dimensional microporous structure, and its high aspect ratio. The thickness of AMH-3 was too thick to prepare appropriate multilayer. Thus, AMH-3 was modified by acid-treatment. Original AMH-3 was delaminated into individual layer. Self-assembled multilayers onto Nafion are prepared using Modified AMH-3 and poly(diallyldimethyl ammonium chloride), PDAC through layer-by-layer method. The increasing number of multilayers resulted in decreased methanol permeability of modified-Nafion.