Rheological response of soft Solid/Liquid Composites

TL;DR

This paper investigates the rheological behavior of soft solid/liquid composites, specifically PEG droplets in PDMS, using fractional rheology and superposition methods to understand their dissipative responses.

Contribution

It introduces a combined approach of fractional rheology and superposition to analyze complex composite materials' rheology, focusing on PEG/PDMS systems.

Findings

Viscous dissipation scales with droplet volume fraction.

Elastic response remains nearly constant across compositions.

Fractional rheology effectively captures the material's dissipative behavior.

Abstract

Understanding a material's dissipative response is important for their use in many applications, such as adhesion or fracture resistance. In dispersions, the interplay between matrix and inclusions complicates any description. Fractional rheology is conveniently used to fit the storage and loss moduli of complex materials. In conjugation with superposition methods, they allow to better capture the behavior of materials of complex rheology. We study the rheology of soft solid/liquid composites of liquid poly(ethylene glycol) (PEG) droplets in a soft poly(dimethylsiloxane) (PDMS) matrix. We analyze the influence of the droplets through fractional rheology and a time-concentration superposition in the continuous-phase-dominated region. Viscous dissipation increases proportionally with volume fraction, independently of the frequency, whereas the elastic response is almost unchanged.