Mid-Term Report Summary - INTERCOCOS (Interdisciplinary research: Connecting complex plasmas with colloidal dispersions)
The aim of this interdisciplinary project is to improve our understanding of various properties of matter at the most elementary level – the dynamical behavior, the phase transitions and the self-organization of liquids and solids at the individual-particle level. This cannot be done at the atomic level in normal matter, but we can make considerable advances by investigating colloidal suspensions and complex plasmas. Here the embedded microparticles (thickness similar to a human hair) act as “proxy-atoms” whose motion can be followed individually by illuminating them with a laser and viewing the system through a low powered microscope.
Of course, studying the behavior of such systems is interesting in its own right. Colloids are already important in many branches of industry (e.g. paints, hydraulics) and complex plasmas are already on the verge of industrial application (e.g. plasma vapor deposition, solar cells), so that understanding the fundamental properties of these systems will be of benefit not only for increasing our basic knowledge but also from the application point of view. Furthermore, it has turned out that these systems are particularly useful analogs for studying micro- and nano-properties both in three and in two dimensions. Here the important point is the dominance of the boundaries (as the systems get smaller, the boundaries become more prominent, and these boundaries provide other conditions than the material properties in the interior. Finally, colloidal suspensions and complex plasmas are excellent systems for studying the breakdown of cooperative behavior (i.e. the self-organization of matter) when the interparticle interactions are too few and far between.
The last point – why study both systems in such an interdisciplinary way – can be answered quite simply. Colloids “operate” in the regime of thermodynamic equilibrium, i.e. the strong fluid (background) damping interaction ensures that the microparticles are all in the same state. In complex plasmas the background damping is due to very rare collisions with gas atoms, so that the dynamics of microparticles is practically undamped. Hence the two systems offer complementary research opportunities, as well as commonalities in numerical simulations and in experimental particle diagnostics.
In the current ERC funded research period we have achieved significant development in understanding fundamental properties of strongly coupled systems. The major highlights include a microscopic theory of non-equilibrium phase transitions in driven systems – the so-called “laning”, and the complementary experiments. These studies allow us to better understand generic processes of this ubiquitous process, which is known to occur even in crowded pedestrian zones. Another major highlight is the discovery of “anomalous” regimes of heterogeneous crystallization – the “crystallization waves”, which result in the growth of highly anisotropic monocrystals, controlled by tuning properties of the substrate. This discovery may have a profound technological impact, enabling a rapid generation of metastable solids with prescribed anisotropic properties.
Of course, studying the behavior of such systems is interesting in its own right. Colloids are already important in many branches of industry (e.g. paints, hydraulics) and complex plasmas are already on the verge of industrial application (e.g. plasma vapor deposition, solar cells), so that understanding the fundamental properties of these systems will be of benefit not only for increasing our basic knowledge but also from the application point of view. Furthermore, it has turned out that these systems are particularly useful analogs for studying micro- and nano-properties both in three and in two dimensions. Here the important point is the dominance of the boundaries (as the systems get smaller, the boundaries become more prominent, and these boundaries provide other conditions than the material properties in the interior. Finally, colloidal suspensions and complex plasmas are excellent systems for studying the breakdown of cooperative behavior (i.e. the self-organization of matter) when the interparticle interactions are too few and far between.
The last point – why study both systems in such an interdisciplinary way – can be answered quite simply. Colloids “operate” in the regime of thermodynamic equilibrium, i.e. the strong fluid (background) damping interaction ensures that the microparticles are all in the same state. In complex plasmas the background damping is due to very rare collisions with gas atoms, so that the dynamics of microparticles is practically undamped. Hence the two systems offer complementary research opportunities, as well as commonalities in numerical simulations and in experimental particle diagnostics.
In the current ERC funded research period we have achieved significant development in understanding fundamental properties of strongly coupled systems. The major highlights include a microscopic theory of non-equilibrium phase transitions in driven systems – the so-called “laning”, and the complementary experiments. These studies allow us to better understand generic processes of this ubiquitous process, which is known to occur even in crowded pedestrian zones. Another major highlight is the discovery of “anomalous” regimes of heterogeneous crystallization – the “crystallization waves”, which result in the growth of highly anisotropic monocrystals, controlled by tuning properties of the substrate. This discovery may have a profound technological impact, enabling a rapid generation of metastable solids with prescribed anisotropic properties.