Dynamics in colloid and protein systems: Hydrodynamically structured particles, and dispersions with competing attractive and repulsive interactions

摘要

In this thesis, we develop and apply a toolbox of versatile theoretical methods of calculatingstructural, and short-time and long-time dynamic properties of three classes ofindustrially important dispersions. The rst one are suspensions of hydrodynamicallystructured colloidal particles, and here most notably non-ionic microgels. The second classare dispersions of submicron sized charge-stabilized colloidal globules, and the third oneare globular protein solutions with competing short-range attraction (SA) and long-rangerepulsion (LR). The results for the transport, structure, and thermodynamic properties ofcharge-stabilized colloids are used as input in our realistic macroscopic diusion-advectionmodeling of the membrane cross-ow ultraltration of silica particles dispersions. Thethesis bridges thus the gap from the theoretical exploration of intra-particle propertiessuch as solvent permeability, particle softness, and surface charge, to the calculation oftransport, structural, and thermodynamic properties of concentrated dispersions, and tothe modeling of a technologically important ltration process. The accuracy of our toolboxmethods is assessed by the comprehensive comparison with experimental measurementsof, and simulation results for static and dynamic properties. The considered dynamicproperties include short- and long-time self-diusion and sedimentation coecients, thewavenumber-dependent diusion function determined routinely in dynamic scattering experiments,and the zero- and high-frequency shear viscosities.In particular, we provide various analytic transport coecient expressions for rigid permeableparticles that can be readily used for the analysis of dynamic scattering and rheologydata. The toolbox methods for the calculation of transport properties of concentrated dispersionsof globular colloidal particles with internal hydrodynamic structure are based onthe hydrodynamic radius model (HRM) wherein the internal particle structure is mappedon an eective hydrodynamic radius for unchanged direct interactions. The good performanceof the HRM is demonstrated by comparison with dynamic light scattering experimentson concentrated suspensions of solvent permeable non-ionic microgels. Furthermore,we quantify the eect of particle softness and permeability on the dynamics of ionic microgelsuspensions, and we characterize the particle interactions and microstructure inpolydisperse amphoteric microgel systems in the zwitterionic regime. [...]