Advances in hybrid thin film composite membranes: The untraveled route of non-aqueous interfacial polymerization

Interfacial polymerization is a very flexible technique in which polymerization occurs at the interface between two immiscible phases. It allows for fabrication of thin and defect-free membrane films that can be used in various applications, such as nanofiltration, gas separation and gas barriers. Normally, the polymerization reaction takes place between two reactive monomers, one in water and one in an organic solvent. However, many interesting reactants, including amines and alcohols with complex topologies, are difficult to dissolve in water. This thesis focuses on nonaqueous interfacial polymerization techniques for new thin film materials from monomer combinations that previously could not be used in interfacial polymerization. With the proposed technique, a series of cyclomatrix polyphosphazene networks are synthesized and their properties and performance are tuned for various industrial application demands. In Chapter 2, the effects of some of these parameters on the properties and the performance of IP-derived polyPOSS-imide thin film composite membranes for hot gas separation are explored, and the scale-up potential of these membranes is evaluated. In the second part of this thesis, a non-conventional IP platform is introduced that makes use of two immiscible organic solvents and provides opportunities for a broadened range of monomer combinations. In the next chapter, another hybrid network is assessed for gas separation at high temperatures. Chapter 3 reports on the formation of thin-film composite cyclomatrix polyphosphazene membranes via the interfacial polymerization reaction between polyhedral oligomeric silsesquioxane and hexachlorocyclotriphosphazene, on top of ceramic support. In chapters 4, 5, and 7 we introduce a series of poly(phenoxy) CPPz membranes. The structure-property relationships of ploy(phenoxy) CPPz are extensively studied. The length, flexibility, and cross-linking extent of the organic bridges between the HCCP core can be varied via the selection of different precursors. Accordingly, the application of those membranes could be changed from hot hydrogen gas selective membranes to (hydrogen) gas barriers and organic solvent nanofiltration. In chapter 6, we pyrolyzed CPPz networks that were obtained from the IP reaction between 1,3,5-trihydroxybenzene (THB) or m-dihydroxybenzene (MDHB) and HCCP.