Entropy production in model colloidal suspensions under shear via the fluctuation theorem

Area of Science:

• Complex fluid dynamics
• Non-equilibrium thermodynamics
• Statistical mechanics

Background:

• Dissipative systems can display counterintuitive properties, such as negative entropy production in simple liquids under shear.
• Non-equilibrium fluctuation theorems provide a framework for understanding these phenomena.

Purpose of the Study:

• To investigate how fine-tuning the properties of complex fluid components influences their non-equilibrium response.
• To control the probability distribution of shear stress and the occurrence of negative entropy production states.

Main Methods:

• Nonequilibrium molecular dynamics simulations were employed.
• The impact of liquid matrix size on negative entropy states was characterized.
• The effect of adding larger particles (colloidal suspension) was analyzed.

Main Results:

• The size of the liquid matrix influences the probability and timescale of observing negative entropy states.
• Introducing larger particles into the liquid matrix significantly increases the occurrence of negative entropy production.
• Modifications in mixture composition and component properties enhance the probability of observing states with negative entropy production.

Conclusions:

• Fine-tuning complex fluid composition can steer non-equilibrium behavior.
• Increased occurrence of negative entropy production suggests a greater propensity for systems to temporarily reverse their thermodynamic trajectory.
• This work offers insights into controlling the directionality of processes in dissipative systems.