Conductivity of Porous Phosphate-Silicate Glass Synthesized with Non-Ionic Surfactant

Porous, phosphate-silicate glass with high-conductivity and nano-size pores was synthesized through a xero-gel route, using non-ionic surfactant polyethylene glycol monocetyl ether (Brij 56) to control pore size. The influences of Brij 56 concentration on pore size and conductivity under different humidity were studied by measuring conductivity and calculating the volume ratio of adsorbed-water to pore volume. Samples prepared with 0.1 wt% Brij 56 had 5.2 nm pore size, 0.91 volume ratio, and narrower pore size distribution than other samples. The nano-size pores were filled with water, which in pores of 5.2 nm is mostly chemically bonded with the hydroxyl groups on the pore surfaces, resulting in higher conductivity than other samples in high relative humidity (over 55%).