Feedback-controlled relaxation pathways of responsive colloids

• Applicant: Professor Dr. Joachim Dzubiella
• Subject Area: Statistical Physics, Nonlinear Dynamics, Complex Systems, Soft and Fluid Matter, Biological Physics ; Experimental and Theoretical Physics of Polymers
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 431945604

This project (P6 of the RU) focuses on the understanding and theoretical description of internal, time-delay feedback effects in the nonequilibrium relaxation of liquid dispersions of responsive colloidal microgels. These soft, stimuli-responsive macromolecules exhibit size variations in response to external stimulation, making them essential for applications such as drug delivery and catalysis which are intrinsically in nonequilibrium. The project aims to investigate how internal degrees of freedom (DoFs), particularly particle size, influence the global relaxation dynamics of these colloids when they are perturbed and transition between equilibrium states. Using Brownian dynamics simulations and coarse-grained theoretical models, the study will analyze how the timescale of the feedback from the internal DoFs affects the time-evolution of macroscopic observables such as density and structural order parameters. The project will develop reduced – time-local and time-nonlocal – models that rationalize the observed relaxation pathways (in a reduced, low-dimensional phase space) of the nonequilibrium liquids. The project will thus not only advance our fundamental understanding of the nonequilibrium relaxation of complex liquids, but also help designing adaptive materials with programmable and highly nonlinear responses. By integrating particle-resolved computational simulations with reduced theoretical models in nonequilibrium, Project P6 contributes signifcantly to the overarching goals of the RU.

• DFG Programme: Research Units
• Subproject of: FOR 5099: Reducing complexity of nonequilibrium systems
• International Connection: Spain
• Co-Investigator: Professorin Dr. Tanja Schilling
• Cooperation Partner: Professor Dr. Arturo Moncho Jordá