Synthesis of organosiloxane-based inorganic/organic hybrid membranes with chemically bound phosphonic acid for proton-conductors

摘要

Proton conductive inorganic-organic hybrid membranes were synthesized from 3-glycidoxypropyltrimethoxysilane (GPTMS) and phosphonoacetic acid (PA) with various ratios by a sol-gel process. Self-standing, homogeneous, highly transparent membranes were synthesized. TG-DTA analyses indicated that these membranes were thermally stable up to 200℃. The results of FT-IR and 13{sup left}C NMR revealed that phosphonic acid groups of PA were chemically bound to organosiloxane network as a result of reaction between PA and GPTMS. The leach out of phosphonic acid groups from GPTMS-PA to water was reduced compared with phosphoric acid groups from GPTMS-H{sub}3PO{sub}4 The proton conductivity of the hybrid membranes increased with phosphonic acid content. The conductivity of GPTMS/PA with a 1/1.05 ratio at 130℃ was 8.7 × 10{sup}(-2) S cm{sup}(-1) at 100% relative humidity (RH).