Emulsification of oil from a subsurface spill and keeping it stable in the water is an important component of the natural remediation process. Motivated by the need to find alternate dispersants for emulsifying oil following a spill, we examine particle-stabilized oil-in-water emulsions. Emulsions that remain stable for months are prepared either by adding acid or salt to carboxyl-terminated carbon black (CB) suspension in water to make the particles partially hydrophobic, adding the oil to this suspension and mixing. When naphthalene, a model potentially toxic polycyclic aromatic hydrocarbon, is added to octane and an emulsion formed, it gets adsorbed significantly by the CB particles, and its transport into the continuous water is markedly reduced. In contrast to an undesirable seawater-in-crude oil emulsion produced using a commercially used dispersant, Corexit 9500A, we demonstrate the formation of a stable crude oil-in-seawater emulsion using the CB particles (with no added acid or salt), important for natural degradation. The large specific surface area of these surface functionalized CB particles, their adsorption capability and their ability to form stable emulsions are an important combination of attributes that potentially make these particles a viable alternative or supplement to conventional dispersants for emulsifying crude oil following a spill.

We engineer novel structures by “stuffing” the aliphatic regions of self-assembled aggregates with hydrophobic homopolymer. These “stuffed” vesicles and multiple emulsions are formed in a one-step process when we rehydrate stuffed films made of amphiphilic block copolymer and hydrophobic homopolymer. Without such homopolymer, this system forms micelles. With homopolymer, vesicles form; varying vesicle membrane thicknesses show that these structures incorporate different amounts of homopolymer. Multiple emulsions, containing more homopolymer than stuffed vesicles, are also fabricated using this single-amphiphile system. The system's incorporation of homopolymer to modify the properties and morphology of the resultant structures is a convenient strategy for preparing self-assembled macromolecular structures with controllable properties.

Grazing incidence X-ray diffraction (GIXD) and Brewster angle microscopy (BAM) were used to study the miscibility and phase behavior of Langmuir monolayers composed of a mixture of a saturated (stearic) and a trans-monounsaturated (elaidic) fatty acid. In contrast with suggestions from previous thermodynamic measurements, these compounds were poorly miscible in monolayers, and phase separation was always observed between domains of a liquid crystalline stearic acid-rich phase and a disordered elaidic acid-rich phase. The molecular packing density inside the ordered domains of mixed monolayers was within 2% of the density of pure stearic acid monolayers at the same surface pressure, suggesting that this phase contained at most a very small fraction of the larger elaidic acid molecules. However, the presence of this small concentration of unsaturated chains depressed the L2 to Ov phase transition by ∼7 mN/m.