Title of the PhD project: Controlling encapsulation and release by charge regulation in macromolecules (Combining simulations with experiments)

Contact person and project supervisor: Dr. Peter Košovan, peter.kosovan@natur.cuni.cz

Research group: Soft Matter

Department: Physical and Macromolecular Chemistry

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.

Project summary:
Two-phase systems based on polyelectrolyte gels or coacervates are potential candidates for charge-based protein sequestration, while polymers modified by boronic acids are capable of sugar sensing. Their common feature is a chemical reaction inside the system, coupled to partitioning of solutes between the system and the bulk solution [1,2]. Experimental studies of such systems have long shown a deficit in theoretical support, partly due to the lack of suitable simulation methods.

We have recently introduced the Grand-reaction ensemble method which enables simulating reactive polymer systems in equilibrium with a reservoir [2]. Within the proposed 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 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.

[1] 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

[2] 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: Background in Physical Chemistry, Soft Matter or Polymer Science. Experience with molecular simulations, programming or Linux.

Our Offer:

Competent and interdisciplinary work environment, where theoretical and experimental research is conducted hand-in-hand.
Work in an international group in the beautiful city of Prague.
Participation at international conferences and workshops.
Collaborations and further scientific training through international partners.
Funding from the Czech Science Foundation grant 19-10429S “Controlling encapsulation and release by charge regulation and multivalent interactions with supramolecular polymer carriers.” allows to increase the salary above the guaranteed minimum of 20500CZK.
Funding resources:

GAČR 19-10429S Controlling encapsulation and release by charge regulation and multivalent interactions with supramolecular polymer carriers
GAČR 21-31978J Simulations of reaction equilibria in polymer systems – method development and applications


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