Nanoparticles for Oil Dispersants and Nano Tracers

Nanoparticles are promising candidates to improve the efficiency of various activities in oil and gas industry such as reservoir characterization, enhanced oil recovery, and oil dispersion due to their large surface area, interfacial activity, and tunable chemical properties. In this dissertation, the potential of surface modified inorganic nanoparticles as oil dispersants and nanosensors were examined and their behaviors were investigated. Silica nanoparticles with hydrophilic poly(oligo(ethylene oxide) monomethyl ether methacrylate) (POEOMA) homopolymer brushes were tested as oil dispersants. These hybrid nanoparticles successfully reduced hexane – water interfacial tension at low nanoparticle concentrations and oil – water emulsions formed using the nanoparticles were stable for more than 60 days. To increase interfacial activity, hydrophilic polystyrene (PS) chains were extended from the homopolymer grafted nanoparticles and synthesized amphiphilic P(OEOMA-b-sty) block copolymer grafted nanoparticles. The copolymer grafted nanoparticles presented improved interfacial activity and oil dispersion capacity. Oil – water emulsions formed by the copolymer grafted nanoparticles showed excellent stability and became solidified hard emulsions after 10 days. For both homopolymer and copolymer grafted particles, hydrodynamic diameters were the key parameter to determine their efficiency as oil dispersants. Cryo-scanning electron microscopy was used to investigate the behavior of the hybrid nanoparticles at oil – water interfaces and the micrographs showed the segregation of the hybrid nanoparticles and their unique void-compensating behavior. Transport behavior of negatively charged carbon nanoparticles in porous rock cores was also examined using single phase core flooding experiments and 1-dimesional convection-dispersion equation. Temperature dependence of transport parameters such as dispersion coefficients and retardation factors were evaluated. The retardation factors were inversely proportional to the rock permeabilities due to particle retention effects. Florescence microscopy revealed that the carbon nanoparticles were preferentially absorbed on the carbonate rock rather than the sandstone rock due to the surface charge effects.Chemical and Biomolecular Engineering, Department o

Interfacial Activity of Poly[oligo(ethylene oxide)–monomethyl ether methacrylate]-Grafted Silica Nanoparticles

The interfacial behavior of water-soluble poly­[oligo­(ethylene oxide) monomethyl ether methacrylate], grafted from 15-nm-diameter silica nanoparticles using a living atom-transfer radical polymerization technique, was examined for hexane and water interfaces. The polymer-grafted nanoparticles reduced the hexane–water interfacial tension from ∼50 to ∼20 mN/m at concentrations of silica in the range of 1–10 ppm. The hydrodynamic size of the dispersed hybrid nanoparticle, a function of the molecular weight of the polymer and grafting density, was the dominant variable in determining the critical particle concentration and efficacy of the hybrid nanoparticles in reducing the hexane–water interfacial tension. A simple phenomenological model is used to explain the strong dependence of the critical particle concentration on the effective hydrodynamic size of the nanoparticles. Water–hexane and water–squalene emulsions formed using 1000 ppm of hybrid nanoparticles were stable for more than 60 days

Interfacial Activity of Poly[oligo(ethylene oxide)–monomethyl ether methacrylate]-Grafted Silica Nanoparticles

The interfacial behavior of water-soluble poly­[oligo­(ethylene oxide) monomethyl ether methacrylate], grafted from 15-nm-diameter silica nanoparticles using a living atom-transfer radical polymerization technique, was examined for hexane and water interfaces. The polymer-grafted nanoparticles reduced the hexane–water interfacial tension from ∼50 to ∼20 mN/m at concentrations of silica in the range of 1–10 ppm. The hydrodynamic size of the dispersed hybrid nanoparticle, a function of the molecular weight of the polymer and grafting density, was the dominant variable in determining the critical particle concentration and efficacy of the hybrid nanoparticles in reducing the hexane–water interfacial tension. A simple phenomenological model is used to explain the strong dependence of the critical particle concentration on the effective hydrodynamic size of the nanoparticles. Water–hexane and water–squalene emulsions formed using 1000 ppm of hybrid nanoparticles were stable for more than 60 days

Mechanical Reinforcement of Epoxy with Self-Assembled Synthetic Clay in Smectic Order

Epoxy films containing self-assembled 2D colloidal α-zirconium phosphate nanoplatelets (ZrP) in smectic order were prepared using a simple, energy-efficient fabrication process suitable to industrial processing. The ZrP nanoplatelets form a chiral smectic mesophase with simultaneous lamellar order and helical arrangements in epoxy. The epoxy nanocomposite films are transparent and flexible and exhibit exceptionally high tensile modulus and strength. The findings have broad implications for development of multifunctional materials for engineering applications