Dynamics and Stability of Emulsified Systems

Emulsified systems consist of two immiscible fluids in which one phase is dispersed as droplets within the other. Their stability and dynamic behaviour arise from the interplay between interfacial tension, viscous forces and stabilising agents such as surfactants or colloidal particles. Surfactants adsorb at the oil–water interface to lower interfacial tension and create steric or electrostatic barriers to coalescence, while particles can form jammed shells that arrest interfacial motion and impart solid-like mechanical properties. External stimuli—temperature changes, shear flows or electric fields—can trigger interfacial phase transitions, droplet deformation, faceting, self-emulsification or rupture. Understanding these phenomena at molecular and continuum scales enables the rational design of emulsions with tailored lifetimes, controlled release characteristics and dynamic responsiveness. This insight underpins advances in pharmaceuticals, food science, enhanced oil recovery and environmental remediation, where precise control over droplet generation, stability and collapse is essential.

Research from Nature Portfolio

Efficient self-emulsification has been achieved by applying narrow-range thermal cycling to preformed emulsions. Repeated cooling–heating cycles induce three distinct droplet breakup mechanisms—including interfacial curvature reversal and lipid crystal dewetting—yielding micrometre and submicrometre droplets from larger ones without high surfactant concentrations. This approach offers a scalable route to fine emulsions and particulate drug carriers, compatible with temperature-sensitive compounds. A predictive framework now describes how surfactant layer properties and thermal history govern droplet fragmentation, providing design principles for industrial emulsification processes.

Dynamics and Stability of Emulsified Systems publication trend

The graph below shows the total number of articles in dynamics and stability of emulsified systems across all publications each year (not limited to Nature Index journals).

Technical terms

Interfacial tension: The energy per unit area at the boundary between two immiscible liquids, driving droplet minimisation of surface area.

Surfactant: A molecule that adsorbs at an oil–water interface to reduce interfacial tension and stabilise droplets against coalescence.

Pickering emulsion: An emulsion stabilised by solid particles that form a rigid or jammed shell at the droplet interface.

Janus nanoparticle: A colloidal particle with two surfaces exhibiting distinct physical or chemical properties, used to tailor interfacial behaviour.

Self-emulsification: Spontaneous generation of fine droplets from larger ones induced by controlled changes in temperature, solvent composition or curvature of surfactant layers.

References

1. Efficient self-emulsification via cooling-heating cycles. Nature Communications (2017).
2. Deformation and rupture of Janus nanoparticle-stabilized Pickering emulsion in confined channel. Chemical Engineering Journal (2024).
3. “Magic Numbers” in Self‐Faceting of Alcohol‐Doped Emulsion Droplets. Small (2023).
4. Opening and Closing of Particle Shells on Droplets via Electric Fields and Its Applications. ACS Applied Materials & Interfaces (2019).