The stability of foam is investigated experimentally through coalescence events. Instability (coalescence) occurs when the system is submitted to external perturbations (T1) and when the liquid amount in the film network is below a critical value. Microscopically, transient thick films are observed during film rearrangements. Film rupture, with coalescence and eventual collapse of the foam, occurs when the available local liquid amount is too small for transient films to be formed. Similar experiments and results are shown in the two-bubble case.

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The anisotropic mechanical properties of bovine eye lenses were measured using cavitation rheology over a range of length scales. The technique involves inducing a cavity at the tip of a syringe needle in different regions of the lens. Effective Young's moduli of the nucleus and cortex of the lens were determined, as approximately 11.8 and 0.8 kPa, respectively, on macroscopic length scales. We also measured the mechanical properties of the lens on the length scale of a single cell, suggesting that the stiffness significantly decreased from that in the bulk measurements for both the nucleus and cortex. In addition, during the growth of the cavity anisotropic propagation in the cortex was observed, while in the nucleus, the propagation was isotropic. We further explored the elasticity of the cavity deformation, showing both elastic and inelastic deformation occurred in the nucleus with equal contributions while deformation in the cortex was elastic and reversible.

Cavitation rheology is a recently developed measurement method for studying the mechanical properties of polymer gels from sub-micron to millimeter length scales at arbitrary locations within the network material. Current knowledge has focused on understanding the relationship between materials properties, such as modulus or fracture strength, and the maximum pressure for initiating cavitation. After the maximum pressure is reached, the growth of the bubble and the associated pressure drop is sudden and uncontrolled. We develop methods to control the growth of the bubble and to understand the relationship between cavity growth, pressure drop, and the material properties of the surrounding polymer network. We conduct these measurements on swollen networks of a triblock copolymer of poly(methyl methacrylate)-poly(n-butyl acrylate)-poly(methyl methacrylate) (PMMA-PnBA-PMMA).

In this paper, we present a new route to mitigate surfactant retention in chemical EOR projects. Surfactants retention, either through adsorption on reservoir rocks or phase trapping, is one of the main constraints to achieve high performance and economical chemical EOR. Specific injection strategies thus need to be developed to mitigate surfactants retention. The use of alkaline and/or salinity gradient approaches present the disadvantage of being restricted to very specific conditions. For example, in hard brine environments, alkalis cannot be used because they can cause scaling. In an offshore environment, as sea water is the only injection water available, water treatment is required in order to use alkali or to perform a salinity gradient. The new route to mitigate adsorption proposed in this paper is based on the use of specific, cost effective, chemical additives which allow mimicking the effect of salinity gradient. The resulting processes, when properly optimized, can achieve very high performances in terms of oil recovery with a limited amount of injected chemicals. Final performance, at lab scale, is comparable to the highly performing ASP/ SP processes in soft brines with salinity gradient.