Presentation materials
The capture of solid particles in a porous medium is critical for many processes but has a major drawback: internal fouling due to pore clogging. Clogging at pore scale is now well understood for inert and rigid particles, but the study of bio-clogging - clogging by biological objects, e.g. living cells - opens many topical research questions as living cells have particular properties that may...
Adsorption-induced deformation is widely observed in porous materials such as cement, coal, clay, aerogel, biopolymers, and MOFs. Sorption swelling has been commonly explained by the so-called Bangham effect (Bangham and Fakhoury 1928), i.e. the relaxation of solid-fluid interfacial tension due to adsorption and thus the macroscopic expansion of the porous media. However, experimental studies...
A notable part of active research on engineered barrier systems for the safe disposal of nuclear waste involves finding and understanding appropriate buffer materials. A buffer material which acts as a barrier between a nuclear waste canister and the surrounding host rock must possess certain properties, some as low-permeability, resistance to contaminant transport, ability to withstand high...
Coal bed methane (CBM), also known as coalbed gas, has drawn much attention lately as an alternative energy resource. Production curves of CBM reservoirs are very different, however, from the ones of hydrocarbon conventional reservoirs (Wang et al., 2011). As emphasized by several studies (Mostaghimi et al., 2017), transport and poromechanical properties of coal are strongly driven by...
Superabsorbent polymer hydrogels are a class of porous media with only two phases (solid and liquid) that have the ability to swell more than 200 times their original volume when placed in water. This feature stems from its unique structure which consists of long polymer chains linked together in a weakly cross-linked network, and the presence of hydrophilic sites along the polymer chains....
Hydrogels are polymeric materials that can absorb large amounts of water, swelling and increasing considerably in size. They are used in a wide range of applications, including some in which the hydrogel is required to absorb liquid under pressure. For example, for soil remediation and water storage in agriculture, hydrogels maybe located deep underground and must withstand the mechanical...
Wrinkling, buckling and creasing instabilities are some of the most familiar phenomena observed in the study of soft materials including hydrogels. They arise when there is mechanical confinement, for example from a fixed base or from hoop stresses in swelling spheres, leading to the preferential formation of wrinkles to relieve shear stresses from the confining strain. These have long been...
Hydrogel actuators are typically made of a bilayer gel that can promote water diffusion in one of the layers, subsequently inducing bending. Here, we show that similar bending behavior can be achieved by simply drying a hydrogel disk on a substrate. By varying the gel’s aspect ratio and the substrate surface energy we are able to either observe (1) a deposit stuck to the substrate, (2) the...
It has been previously observed that when polymer gels (e.g. hydrogels) undergo rapid extensive swelling, a transient crumpling instability can form on the surface of the gel. This instability consists of many line segments of cusps patterning the gel's surface into an array of bumps that arise from shear bending of a homogeneously swollen gel surface
Here, we present experiments showing...
