Rheological Behavior of Emulsion-Filled Gels

Emulsion-filled gels comprise a soft solid matrix in which dispersed droplets of one liquid phase are embedded within a gel network formed by polymers, proteins or polysaccharides. The rheological behaviour of these complex colloidal systems arises from the interplay between droplet–matrix interactions, droplet size and distribution, and the intrinsic viscoelasticity of the continuous gel phase. Under small deformations, emulsion-filled gels typically exhibit a solid-like response characterised by an elastic modulus (G′) that reflects the strength of the percolated network. As strain increases beyond the linear viscoelastic regime, non-linear characteristics such as yielding, shear thinning and strain-hardening or softening become prominent. The introduction of emulsion droplets can reinforce the gel structure by acting as active or passive fillers, depending on interfacial adhesion, or destabilise it by promoting phase separation or localised stress concentrations. Microstructural parameters—such as droplet clustering, network porosity and crosslink density—govern the transition between elastic and plastic regimes and influence thixotropic recovery after shear. These properties are critical for the design of food textures, pharmaceutical carriers, biomedical scaffolds and personal-care formulations, where mechanical integrity must be balanced with sensory or functional performance. Recent advances in tailored droplet–matrix chemistry, multi-scale structural characterisation and mechanistic modelling have expanded our capability to predict and tune the flow and deformation behaviour of emulsion-filled gels for diverse applications and manufacturing processes.

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Rheological Behavior of Emulsion-Filled Gels publication trend

The graph below shows the total number of articles in rheological behavior of emulsion-filled gels across all publications each year (not limited to Nature Index journals).

Technical terms

Emulsion-filled gel: a composite soft material in which dispersed liquid droplets are entrapped within a gel matrix.

Viscoelasticity: the combined viscous and elastic response of a material under deformation.

Small amplitude oscillatory shear (SAOS): a rheological test applying low-strain oscillations to measure linear viscoelastic moduli.

Large amplitude oscillatory shear (LAOS): a rheological method involving high-strain oscillations to probe non-linear material behaviour.

Yield stress: the critical stress at which a material begins to flow or yield from a predominantly solid-like state.

References

1. Rheology of Emulsion-Filled Gels Applied to the Development of Food Materials. Gels (2016).
2. Clustering of oil droplets in o/w emulsions: Controlling cluster size and interaction strength. Food Research International (2019).
3. Effect of oil droplet inhomogeneity at different length scales on mechanical and sensory properties of emulsion-filled gels: Length scale matters. Food Hydrocolloids (2020).
4. Rheology, Microstructure, and Storage Stability of Emulsion-Filled Gels Stabilized Solely by Maize Starch Modified with Octenyl Succinylation and Pregelatinization. Foods (2021).