Ultrathin layers of positively charged poly(diallyldimethylammonium chloride) (PDDA) and negatively charged poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPS) were alternately deposited on the negatively charged phenylsilsesquioxane (PhSiO3/2) particles via Layer-by-Layer (LbL) technique. PDDA/PAMPS multilayer-deposited PhSiO3/2 particles once soften and glued together with plastic deformation at temperatures higher than the glass transition temperature. Sheet-like electrolytes prepared using multilayered PDDA/PAMPS-deposited PhSiO3/2 particles showed proton conductivities 4-6 orders of magnitude higher than those of the samples without multilayers, and the proton conductivity reached about 10(-3) S/cm at 80 degrees C and 80% relative humidity. (C) 2009 Elsevier B.V. All rights reserved.