An insight into the structure–property relationships of PECVD SiCxNy(O):H materials

The structure–properties relationships of SiCxNy(O):H PECVD gas selective membranes are investigated. Both atomic and chemical bond concentrations in the thin films are determined experimentally to build a 3D atomic cluster description of the materials, thus explaining and correlating well with the He and N2 transport properties of the membranes. [Display omitted] •Structure/property relationships of SiCxNy(O):H PECVD materials were investigated.•Atomic and chemical bond concentrations were determined.•3D atomic description was proposed.•Atomic models account for gas transport properties of the as-prepared materials. In this work the structure–property relationships of SiCxNy(O):H gas separation membranes prepared by PECVD is investigated. X-ray photoemission spectroscopy, fast Fourier transform infra-red spectroscopy and X-ray reflectometry are used to determine both the atomic and chemical bond concentrations in the PECVD membrane materials. Coupling these experimental data with a continuous random network model (cluster approach), a 3D molecular description of the material is proposed. It is shown that such approach can depict the composition and the electronic density of the PECVD SiCxNy(O):H, thus providing description of material porosity that accounts for the measured gas transport properties of both He and N2 through the membranes.