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Séminaire Guido Falk

From Colloids to Nanomaterials in two and three dimensions : The impact of additional external fields

Guido Falk

Powder Technology of Glass and Ceramics
Saarland University, Germany

Modern aspects in ceramic material science incorporate a multidisciplinary understanding of transport, adsorption and adhesion of particles and colloids at interfaces in order to tailor the microstructure of these advanced materials in the nano- and submicro domain. The role of interparticle and external forces, i.e. application of external electrical fields during shaping process, achieved considerable attention in order to guarantee ´self-assemble´ consistent coordination of nanoparticulate green structures and highest qualities of 2D and 3D functional nanoceramic materials.

In this talk I will present recent experimental results on field assisted processing and characterization of nanoparticle derived ceramics. Some examples of ceramic multilayer and monolithic ceramics as well as ceramic foams and composites with advanced optical, electrical and thermo-mechanical characteristics will be presented.

In particular membrane electrophoretic particle capture and deposition can give rise to colloidal crystal bulk and layer formation. Incorporated electrokinetic effects are modelled and applied to a multi-physical approach incorporating highly coupled governing equation for the particle EDL (Poisson-Boltzmann equation), ion concentrations (extended Nernst-Planck-equation) as well as electrolyte and liquid phase flow (Navier-Stokes equation).

Finally I will present some recent results for impinging jet deposition of nanoparticles. The interplay of boundaries and an external electrical field yields a complex non-linear flow behaviour, which is modelled by a convection-diffusion-migration approach.