Deposition of Ultrathin Nafion Layers on Sol–Gel-Derived Phenylsilsesquioxane Particles via Layer-by-Layer Assembly

Abstract

Ultrathin layers of oppositely charged poly͑diallyldimethylammonium chloride͒ ͑PDDA͒ and Nafion were alternately deposited on negatively charged phenylsilsesquioxane ͑PhSiO 3/2 ͒ microparticles via layer-by-layer assembly. An extremely small amount of Nafion was used for the layers. The average thickness of a Nafion layer was estimated to be 2.6 nm from the amount of deposited Nafion and the density. A monolithic sheet was obtained from PhSiO 3/2 particles with PDDA and the Nafion multilayer when the particles were pressed at 70 MPa. Fenton's test, differential thermal analysis, and thermogravimetry revealed that PhSiO 3/2 particles are chemically and thermally stable. The monolithic samples prepared using PDDA/Nafion-multilayer-coated PhSiO 3/2 particles showed proton conductivities ϳ4 orders of magnitude higher than those of samples without multilayers, and their conductivity reached about 10 −5 S/cm at 80°C and 80% relative humidity.

Enhanced hollow fiber membrane performance via semi-dynamic layer-by-layer polyelectrolyte inner surface deposition for nanofiltration and forward osmosis applications

“…Compared with the traditional Langmuir-Blodgett thin-film deposition method, the ease of film formation and film stability and versatility are the main advantages of this new technique [1]. Based on the combination of various polyelectrolyte pairs and substrates, the LBL assembled membranes have been studied for a wide range of applications such as pervaporation [2,3], fuel cell [4], nanofiltration (NF) [5,6] and wastewater treatment [7].…”

Polyelectrolyte complex membranes for pervaporation, nanofiltration and fuel cell applications

“…(H 3 PW 12 O 40 :WPA) [189] and the other is composed of PDDA and Nafion [190]. Their results showed that the proton conductivities of particles coated by WPA/PDDA and Nafion/PDDA multilayered PEC membranes were about 10 −4 and 10 −5 S cm −1 , which were 4 orders of magnitude higher than those of pristine phenylsilsesquioxane particles.…”

Effects of tin phosphate nanosheet addition on proton-conducting properties of sulfonated poly(ether sulfone) membranes

“…It has been reported that the chemical, thermal, and mechanical stabilities of membranes can be improved by dispersing an inorganic filler in the organic matrix. It has also been reported that rapid ionic transfer through the interface between the two different materials occurs in some proton-conducting organic/inorganic composite materials [12,15]. Higher stabilities, greater proton conductivity, or better fuel-cell performance have been reported for some composite systems such as Nafion/TiO 2 , SPEEK/WO 3 , SPES/ heteropoly acid (H 3 PW 12 O 40 ), SPES/boron phosphate (BPO 4 ), or SPEEK/ organically treated montmorillonite (OMMT) [12][13][14][16][17][18][19].…”