Microrheological model for Kelvin-Voigt materials with micro-heterogeneities

Area of Science:

• Rheology
• Materials Science
• Soft Matter Physics

Background:

• Viscoelastic materials exhibit complex flow and deformation behaviors.
• Characterizing heterogeneities in these materials is crucial for understanding their properties.
• Existing models may not fully capture the nuances of heterogeneous viscoelastic systems.

Purpose of the Study:

• To present a generalized Kelvin-Voigt model for viscoelastic semisolid materials.
• To incorporate and characterize material heterogeneities within this framework.
• To provide analytical tools for studying particle dynamics in such materials.

Main Methods:

• Microrheological approach using probe particle dynamics.
• Derivation of analytical expressions for mean square displacement.
• Development of expressions for the time-dependent diffusion coefficient.
• Validation via Brownian dynamics simulations.

Main Results:

• The generalized Kelvin-Voigt model effectively describes heterogeneous viscoelasticity.
• Analytical expressions for particle displacement and diffusion were derived.
• Model predictions align with Brownian dynamics simulation results.
• Successful application to experimental data from polyacrylamide and LAPONITE® gels.

Conclusions:

• The proposed model offers a robust method for characterizing heterogeneities in viscoelastic materials.
• The microrheological approach provides valuable insights into material microstructure.
• This work bridges theoretical modeling with experimental validation in soft matter research.