Area of research:
The Soft Matter group combines a variety of experimental methods and simulations/theory to investigate self-assembling polymer systems, such as polyelectrolyte solutions, micelles, interpolyelectrolyte complexes or polymer gels. We focus on fundamental understanding of thermodynamic and kinetic aspects of the behaviour of these systems.
Solutions of proteins, peptides or charged synthetic polymers may spontaneously phase-separate, forming a polymer-rich phase (coacervate or precipitate), which is in equilibrium with the polymer-free supernatant solution. This phase separation is often driven by electrostatic interactions, which are determined by the protonation states of acid and base groups which depend on the pH. In general the pH differs between the polymer-rich phase and the buffer solution.
We have recently introduced the Grand-reaction ensemble method which enables simulating reactive polymer systems in equilibrium with a reservoir. Within the project we will further develop this method and apply it to simulations of two-phase systems, addressing specific questions arising from experiments performed by our collaborators within the project, or by our external partners. We will use the computer simulations to predict the properties of both phases: supernatant solution and the coacervate of polyelectrolyte gel. Furthermore, we will use this method to predict the partitioning of small ionic solutes between both phases.
The main job of the student will be to perform the simulations, analyze the data, refine the models and implement new simulation algorithms or new simulation protocols. Optionally, the job may also include experimental investigation of these systems.
 J. Landsgesell, L. Nová, O. Rud, F. Uhlík, D. Sean, Pascal Hebbeker, C. Holm, P. Košovan: Simulations of ionization equilibria in weak polyelectrolyte solutions and gels, Soft Matter (2019) DOI: 10.1039/c8sm02085j
 J. Landsgesell, P. Hebbeker, O. Rud, R. Lunkad, P. Košovan, C. Holm: Grand-reaction method for simulations of ionization equilibria coupled to ion partitioning. Macromolecules, 53(8):30073020, 2020
Features of an ideal candidate:
Required: MSc. or equivalent in Chemistry, Physics or a related field, good knowledge of English
Beneficial: Solid background in Physical Chemistry, Soft Matter or Polymer Science. Experience with molecular simulations, python or other programming language, Linux OS.
Chemistry: Acid-base equilibria in two-phase systems containing proteins, peptide or synthetic polymers, studied by molecular simulations