Polyhedral Oligomeric Silsesquioxane (POSS) Nano-Composite Separation Membranes - A Review

Nano-composite membranes are developed to overcome the limitation on trade-off effect of permeability and selectivity from commercial membranes, however, careful selection of the nano-fillers is required to match the selection criteria for specific applications. Polyhedral oligomeric silsesquioxane (POSS) nano-particles are studied as the filler for nano-composite membrane design for their unique 3-dimensional building block property and flexible functionality toward the enhancement of separation. The review paper presents the benefits brought by POSS for nano-composite membranes design, systematically compared to pristine or reference membranes. The scope of the review comprehensively includes liquid separation driven by pressure, desalination, solvent separation, gas separation, and proton exchange membranes. The free volume and surface charge modification as well as the structural enhancement from POSS incorporation are highlighted as keys to affect the trade-off between permeation and selectivity and future developments for POSS nano-composite membranes are discussed.