Positron beam study of sol-gel prepared ordered mesoporous silica thin films

Abstract

Several so-gel prepared silica thin films with ordered meso-pores were studied with a variable energy positron beam. Doppler broadening measurements show that in CTAB-templated samples, film porosity is the superior factor upon pore size and affects the final S parameter. While for P123 and F127-templated films with similar porosity, as hexagonal pores extend along the direction parallel to film surface, a larger effective pore size could be sensed by positrons, which enhances open volume ratio favourable for Ps formation.