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Abstract
Nowadays, hybrid inorganic-organic materials, which exhibit characteristics in between the two original phases or even new properties, have already been a fascinating new field of research in materials science. This PhD project is aimed at investigating the influence of composition and interfacial interaction on the morphology, physical properties, and transport phenomenon (proton, liquid, and gas) of three hybrid inorganic-organic material systems. (1) Carbon-Nafion Composites: The wetting properties of carbon-Nafion composites determined by apparent contact angle, Yong’s contact angle, and surface free energy are highly dependent on the composites’ composition, surface roughness, and temperature. These composites exhibit super hydrophobic properties. The surface free energy was evaluated by using four different theories, which are Equation of state, Owens and Wendt’s geometric mean approach, Wu’s harmonic mean approach, and Acid base theory. (2) TEOS-TIP-Penta Block Copolymer(PBC): This work differs in that a ternary phase diagram was constructed to provide fundamental knowledge about the homogeneity and electrospinnability of TEOS-TIP sol-gel system dependent on initial composition and reaction conditions, which leads to the success in the development of novel TEOS-TIP-PBC hybrid materials. These hybrid materials exhibits significant improvement in proton conductivity, alcohol and water uptake, and liquid permeability, which is assigned to the interaction between inorganic components and functional groups along the polymer chains. (3) TEOS-TIP-Polyimide: A series of hybrid inorganic-organic composites based on [6FDA- 6FpDA]-[6FDA-DABA] polyimide block copolymers and various silica-titanium sol-gel networks were successfully synthesized in this study. The gas permeation properties (permeability, diffusivity, and solubility coefficients) and gas separation performances are significantly affected by the nature and content of the metal alkoxides employed. It is believed that the interaction between functional groups along the polyimide backbones and titanium based inorganic structures plays important role in limiting segmental motions, inhibiting packing efficiency of polymer chains, and potentially creating more accessible free volume in the hybrid system without defects, which results in the simultaneous improvement in permeability and selectivity. In conclusion, the fundamental work in this research is expected to advance the development of hybrid inorganic-organic materials and their uses in fuel cells and gas separation.
