Dimethyl silane-modified silica in polydimethylsiloxane as gas permeation mixed matrix membrane

The gas transport behaviors of O 2 , N 2 , CO 2 and CH 4 were investigated in mixed matrix membranes (MMMs) prepared from polydimethylsiloxane (PDMS) filled with surface functionalized silica (SiO 2 ) nanoparticles. SiO 2 surface modification was performed through silanization using chlorodimethyl silane. FTIR confirmed the presence of dimethyl silane on SiO 2 (Si-DMS) whereas elemental analysis showed 94.2% successful modification. Thermal gravimetric analysis revealed the improved thermal stabilities of PDMS MMMs. Field emission scanning electron microscopy revealed the uniform distribution of Si-DMS within the membrane. The effect of Si-DMS in gas permeabilities (P) was in contrast to the Maxwell model prediction. Enhanced P values of all gases in PDMS MMMs (as compared to pure PDMS) were associated to the improvement in diffusion coefficients (D m ) despite the reduction in gas solubility coefficients. The increase in D m values was attributed to the higher free volumes in PDMS MMMs. However, slight declines (