Přehled

Project summary:

Polyelectrolytes are polymer systems which carry ionizable units. Strong polyelectrolytes in solutions are fully ionized, but the degree of ionization of weak polyelectrolytes depends on external conditions, like pH. While the ionization behavior of weak polyelectrolytes in dilute solutions was already studied [1], the opposite is true for more concentrated solutions, i.e. the semidilute regime [2]. Semidilute polymer solutions are used in water-in-salt electrolyte based materials, where polymer chains act either as an inert carrier or even can take part in the electrochemical process. The water-in-salt systems contain low amounts of water and high amounts of salt, which makes the polymer chain properties and ionization behavior difficult to predict. In this project we will investigate the ionization of weak polyelectrolyte systems above overlap concentration. We will focus on the influence of chain architecture; in particular we will study linear chains, stars and combs. We will study the influence of salt content and counterion valency on the ionization of the weak polyelectrolyte chains [3,4,5].

The candidate will perform Monte Carlo/Molecular dynamics simulations of semidilute polyelectrolyte systems with various chain architectures. He/she will use our in-house implementation of Hamiltonian Monte Carlo, but he/she will be also encouraged to write his/her own parts and utilities to the used software. He/she will also participate in method development for efficient sampling of the studied systems. Ideal applicant has a background in computational physical chemistry or chemical physics. He/she has hands-on experience with Monte Carlo, Molecular dynamics and coarse-grained models. He/she is experienced in programing, coding and computing using supercomputer facilities. He/she is self-motivated, initiative/commitment and able to schedule his/her tasks.

References: 

  1. Local pH and effective pka of weak polyelectrolytes – insights from computer simulations. Lucie Nová, Filip Uhlík, and Peter Košovan. Phys. Chem. Chem. Phys., 19:14376–14387 (2017) DOI: 10.1039/C7CP00265C
  2.  When do polyelectrolytes entangle? Andrey V. Dobrynin and Michael Jacobs. Macromolecules, 54(4):1859–1869 (2021) DOI: 10.1021/acs.macromol.0c02450
  3. Salt Counterion Valency Controls the Ionization and Morphology of Weak Polyelectrolyte Miktoarm Stars,  Lucie Nová and Filip Uhlík, Macromolecules, 55 (14), 6247-6259 (2022) DOI: 10.1021/acs.macromol.2c00133
  4. Multivalent counterions accumulate in star-like polyelectrolytes and collapse the polymer in spite of increasing its ionization, Roman Staňo, LucieNová, Filip Uhlí­k, Peter Košovan, Soft Matter 16 (4) 1047-1055 (2020) DOI: 10.1039/C9SM02318F
  5. Interactions of star-like polyelectrolyte micelles with hydrophobic counterions, Roberto Fernandez-Alvarez, Lucie Nová, Filip Uhlík, Sami Kereïche, Mariusz Uchman, Peter Košovan, Pavel Matějíček, Journal of Colloid and Interface Science 546, 371-380 (2019) DOI: 10.1016/j.jcis.2019.03.054


Apply to the project