Theoretical and computational modeling of self-oscillating polymer gels

Area of Science:

• Soft Matter Physics
• Chemical Kinetics
• Polymer Science

Background:

• Chemoresponsive polymer gels exhibit dynamic behavior influenced by chemical reactions.
• The Belousov-Zhabotinsky (BZ) reaction is a well-studied oscillating chemical reaction.
• Modeling wave propagation in gels requires integrating reaction kinetics with material deformation.

Purpose of the Study:

• To develop a computational model for wave propagation in chemoresponsive polymer gels undergoing the BZ reaction.
• To investigate pattern formation and shape changes in these gels.
• To explore the potential for macroscopic motion driven by gel-wall interactions.

Main Methods:

• Modified the Oregonator model to incorporate polymer effects on BZ reaction kinetics.
• Utilized a two-fluid model framework to describe gel dynamics.
• Developed the gel lattice spring model (gLSM) for efficient 2D simulations.
• Incorporated polymer-solvent interactions via a coupling term in the Flory-Huggins model.

Main Results:

• Simulated pattern formation and shape changes in 2D rectangular BZ gels anchored to a wall.
• Demonstrated that dynamic patterns are dependent on gel expansion/contraction near the wall and sample dimensions.
• Observed macroscopic motion of the gel sample due to detachment from the wall.

Conclusions:

• The gLSM is an effective tool for simulating large-scale deformations and reactions in polymer gels.
• Gel-wall interactions significantly influence pattern formation and can induce macroscopic motion.
• This work provides insights into the coupled chemo-mechanical behavior of polymer gels.