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The present work reports the effect of various organically functionalized polyhedral oligomeric silsesquioxane (POSS) particles on the gas transport properties (N2, O2, and CO2 molecules) in poly(vinyl alcohol) (PVA) membranes. The incorporation of polyethylene glycol‐POSS (PEG‐POSS), octa‐tetramethylammonium‐POSS (Octa‐TMA‐POSS) and m‐POSS (Octa‐TMA‐POSS molecule was modified using cetyltrimethyl ammonium bromide) led to the enhancement in CO2 separation performance of PVA, among which, PEG‐POSS exhibited highest CO2 separation due to the dipole‐quadrupolar interaction of CO2 with ethylene oxide group in POSS. Octa‐TMA‐POSS and m‐POSS reduced the O2 and N2 permeability of the PVA membrane due to the reduction in the number of permeating pathways as compared to pure PVA. Free volume of the membranes was evaluated by positron annihilation lifetime spectroscopic (PALS) and coincidence Doppler broadening measurements. PALS confirms the increase in polymer free volume in PVA/POSS system due to the presence of rigid and spherical POSS molecule, which could enter in the polymer chain and provide viable pathway for molecular transport. Maxwel–Wagner–Sillar and Higuchi models were applied for the theoretical prediction of permeability of the fabricated membranes. [ABSTRACT FROM AUTHOR]

Cage ‐ structured polyhedral oligomeric silsesquioxane (POSS) molecules were used as modifiers in the fabrication of poly(vinyl alcohol) (PVA) membrane for the separation of an azeotropic mixture of tetrahydrofuran (THF) and water system. Poly(ethylene glycol) and anionic octa(tetramethyl ammonium)‐functionalized POSS were used for this study. The membranes exhibited excellent water selectivity and permeance because of their preferential interactions toward water molecules in the azeotropic THF–water mixture. In the presence of poly(ethylene glycol)–POSS and anionic octa(tetramethyl ammonium)–POSS, the PVA membrane exhibited a significant increase in selectivity. A modified Maxwell–Stefan equation was used for the computation of the theoretical flux, which was compared with the experimental values. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47060. Poly(vinyl alcohol) (PVA) containing cage structured polyhedral oligomeric silsesquioxane (POSS) molecules as modifier to fabricate a membrane for the separation of azeotropic mixture of tetrahydrofuran (THF) ‐ water system. Polyethylene glycol (PEG) and anionic‐octa(tetramethylammonium) (Octa‐TMA) functionalized polyhedral oligomeric silsesquioxane (POSS) were employed for the present study. The membranes exhibited excellent water selectivity and permeance due to the preferential interaction of membrane towards water molecule in the azeotropic THF‐ water mixture. In the presence of PEG‐POSS and Octa‐TMA‐POSS, PVA membrane exhibited a significant increase in selectivity. Modified Maxwell‐ Stefan equation was used for the computation of theoretical flux and was compared with the experimental values. [ABSTRACT FROM AUTHOR]