Rheological response of soft solid/liquid composites.

Area of Science:

• Materials Science
• Rheology
• Polymer Physics

Background:

• Understanding material dissipative response is crucial for applications like adhesion and fracture resistance.
• The complex interplay between matrix and inclusions in dispersions complicates rheological descriptions.
• Fractional rheology and superposition methods are effective for modeling complex material behavior.

Purpose of the Study:

• To investigate the rheological properties of soft solid/liquid composites.
• To analyze the influence of liquid inclusions on the dissipative and elastic responses of a soft matrix.
• To apply fractional rheology and time-concentration superposition to understand composite behavior.

Main Methods:

• Studied soft composites of liquid poly(ethylene glycol) (PEG) droplets in a poly(dimethylsiloxane) (PDMS) matrix.
• Utilized fractional rheology to model the storage and loss moduli.
• Employed time-concentration superposition in the continuous-phase-dominated region.

Main Results:

• Viscous dissipation increases proportionally with the volume fraction of PEG droplets.
• The increase in viscous dissipation is independent of frequency.
• The elastic response of the PDMS matrix is minimally affected by the presence of PEG droplets.

Conclusions:

• Fractional rheology effectively captures the behavior of these soft composites.
• The volume fraction of inclusions significantly impacts viscous dissipation but not elastic properties.
• This work provides insights into the rheology of soft matter composites for various applications.