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dc.contributor.advisor Jürgen, Vollmer Prof. Dr.
dc.contributor.author Rohloff, Martin
dc.date.accessioned 2015-09-09T09:03:57Z
dc.date.available 2015-09-09T09:03:57Z
dc.date.issued 2015-09-09
dc.identifier.uri http://hdl.handle.net/11858/00-1735-0000-0023-9610-E
dc.language.iso eng de
dc.rights.uri http://creativecommons.org/licenses/by-nc-nd/4.0/
dc.subject.ddc 530 de
dc.title Continuously driven phase separation: size distributions and time scales in droplet growth de
dc.type doctoralThesis de
dc.contributor.referee Müller, Marcus Prof. Dr.
dc.date.examination 2015-07-16
dc.subject.gok Physik (PPN621336750) de
dc.description.abstracteng Phase separation arises in mixtures when temperature, pressure or concentrations of the mixture is changed such that a new macroscopic phase emerges. Typically the domains of the new phase take the form of droplets, bubbles or solid particles. Many phenomena such as the synthesis of monodisperse colloidal particles, rain formation or geysers are caused by continuously driven phase separation where a sustained change of temperature, pressure or concentrations induces a continuous increase of the volume occupied by the domains. I use here (i) laboratory experiments on phase separation of liquid binary mixtures, (ii) numerical investigation of droplet assemblies evolving with overall volume growth, and (iii) theoretical modelling to study the evolution of the domain size distributions and the emerging time scales in the domain growth. Depending on the driving strength I identify a crossover from coarsening dynamics (Ostwald ripening) to size focussing in the domain size distributions. I give analytic expressions for the evolution of the size distribution in the size focussing regime that arises for sufficiently strong driving and I show that the size distribution can be rescaled for all times onto the initial distribution. These findings have immediate consequences for size distributions in nano-particle synthesis. When the droplets have grown to sizes where their motion is affected by buoyancy, sedimentation and collisions cause a runaway growth. The runaway leads to precipitation of the droplet volume out of the fluid and resets the system. For a sustained driving new droplets start to grow and eventually they will be removed by another wave of precipitation. We denote this oscillatory response to a continuous thermodynamic driving as episodic precipitation. The time scale of precipitation is set by the crossover from diffusive to collisional growth. The measured time scales collapse on a master curve predicted by an analytic model that is also developed in the thesis. Applying the model to the formation of warm rain gives reasonable values for the rain initiation time. The application of concepts developed in the present thesis to describe continuously driven phase separation thus provides valuable new insights for a wealth of different phenomena. de
dc.contributor.coReferee Jürgen, Vollmer Prof. Dr.
dc.subject.eng phase separation de
dc.subject.eng binary fluids de
dc.subject.eng ripening de
dc.subject.eng cloud physics de
dc.subject.eng precipitation de
dc.subject.eng monodisperse colloids de
dc.subject.eng size focussing de
dc.subject.eng synchronisation de
dc.identifier.urn urn:nbn:de:gbv:7-11858/00-1735-0000-0023-9610-E-4
dc.affiliation.institute Fakultät für Physik de
dc.identifier.ppn 834791226

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