Diverse Hybrid Polymeric Structures from Pickering Emulsion-Based Templates Stabilized by Graphene Oxide and Its Derivative

Abstract

Fluid-fluid interfaces are not only important for widespread applications such as liquid-liquid extraction, pharmaceutical formulation, mineral processing, etc., but also provide versatile templates for the architecture of advanced structures and materials. This dissertation focuses on developing diverse fluid-fluid platforms (e.g., oil-oil emulsions, oil-water emulsions, bicontinuous emulsions, etc.) assisted by the interfacial assembly of graphene oxide (GO) nanosheets and their derivatives and constructing different application-oriented polymeric hybrid structures through interfacial/dispersion polymerization. The unique interfacial activity and chemical tunability of GO make it an efficient sheet-like surfactant to stabilize the fluids behavior in systems with different polarity and viscosity. The multifunctionality of GO (e.g., rheological modifier, graphene precursor, etc.) imparts the obtained structures with desired properties such as printability and conductivity. Integration of polymers into the system provides the obtained structures with stability, dynamicity, elasticity, and so on, and thus can collect the interest of a broad range of future applications. For instance, by incorporating dynamic covalent bonds into polymer shells prepared from oil-in-oil Pickering emulsions, capsules with multi-transformation pathways including inter-capsule bonding and capsule shell destruction can be achieved. These capsules can be promising feedstock/platforms for selective laser sintering, supercapacitors, and controlled release. Further, through direct ink writing of bicontinuous interfacially jammed emulsion gels (bijels) composed of photocurable resin and water, conductive porous materials with excellent RF heating performance can be successfully obtained without complicated pre/post-processing. Future expansion of employing Pickering emulsion-based systems for producing hybrid polymeric structures concentrates on constructing bijel templates through hybrid particle systems and polymerization of the bijels to get tunable porous hydrogel structures. The applicability of using hybrid particle systems for producing bijels with various oil-water systems is evaluated, after which polymerization of the individual domains of the bijel will be carried out using different monomers/polymer precursors to produce tunable porous structures. The research illustrated in this dissertation provides templates/methodology for the production of various polymeric structures with dynamicity, tunable morphology, mechanical properties, and conductivity for various potential applications in easy-to-process ways without complicated pre/post processing.