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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 15: Poster I
CPP 15.34: Poster
Monday, March 18, 2024, 18:00–20:00, Poster C
Simulation of pH-Responsive Hydrogel Formation — •David Beyer1, Peter Košovan2, and Christian Holm1 — 1Institute for Computational Physics, University of Stuttgart, D-70569 Stuttgart, Germany — 2Department of Physical and Macromolecular Chemistry, Charles University, 128 00 Prague 2, Czechia
Motivated by recent experiments investigating pH-reponsive, electrostatically triggered hydrogel formation (Mons et al., in preparation), we investigate the interaction between permanently charged sulfonate chains and charge-regulating carboxybetaine chains. Through simulations integrating a state-of-the-art Monte Carlo method for charge-regulating systems with a free energy approach, we obtain the potential of mean force between these chains for different pH-values. Our simulations reveal a substantial charge-regulation effect, elevating the stability of the complex to pH-values beyond what the Henderson-Hasselbalch equation would suggest. A comparative study between fully functionalized and 75% functionalized betaines reveals a further significant enlargement of the pH-stability window in the latter scenario. Overall, our simulations provide a comprehensive explanation for the observed stability at much higher pH-values than naively expected, emphasizing the combined impact of these two effects.
Keywords: Weak Polyelectrolyte; Monte Carlo; Molecular Dynamics; Hydrogel; Smart Materials