Tuning colloidal gels by shear


Study the effects of shear and flow history on the structure and properties of model colloidal gels. Different shear protocols including steady/oscillatory shear at different rates/amplitudes will be utilized. Combined rheometry, microscopy, and scattering experiments with simulations will probe structural changes and link them with the mechanical response


Task 2.1: Shear effects in model colloidal gels (M6-36)

           a) Spherical particles will be used in depletion systems and DLVO gels with attractions tuned by the addition of nonadsorbing polymer

                in organic solvents or salt in aqueous systems, respectively. Different shear protocols and computer simulations will be explored to

                rationalize detected structural changes underlying tuning of mechanical properties (D2.1, D2.5)

            b) Anisotropic particles (silica/alumina rods and clay platelets) gels will be explored over large part of phase space to determine effects

               of order-disorder transitions under shear (D2.3)

            c) Development and testing of Rheo-OCT to spatially map structuring/diffusion/ concentration of colloidal gels under shear.

Task 2.2: Shear effects in colloidal gels with large inclusions (M3-36)

Pre-shear effects will be explored in gels seeded with solid particles or gas bubbles with combined rheometry microscopy/DDM/scattering/Rheo-OCT and computer simulations (D2.4)

Task 2.3: Industrial systems and problems (M9-42)

Simplified industrial systems and full formulations will be studied following the pre-shear protocols established (D2.2, D2.6)