[Paper Review] El Fenomeno de Maduracion de Ostwald. Predicciones de las Simulaciones de Estabilidad de Emulsiones sobre la Evolucion del Radio Cubico Promedio de una Dispersion de Aceite en Agua

Germán Urbina-Villalba|arXiv (Cornell University)|Mar 8, 2013

Electrohydrodynamics and Fluid Dynamics3 citations

TL;DR

This study applies Emulsion Stability Simulations (ESS) to model Ostwald ripening in dodecane-in-water nanoemulsions, incorporating electrostatic and hydration forces, drop deformability, and initial size distributions. It predicts the time evolution of the cube-average radius, showing that initial size distribution and interfacial forces significantly influence droplet growth kinetics over minutes post-emulsification.

ABSTRACT

In this chapter, the theory of Lifshitz, Slesov and Wagner and the technique of Emulsion Stability Simulations (ESS) are reviewed. Complementary algorithms required to incorporate the phenomenon of Ostwald ripening in ESS are presented. The simulations are used to study the behavior of dodecane-in-water nanoemulsions as a function of time. The influence of electrostatic interactions, hydration forces, the initial drop size distributions, and the deformability of the drops, are studied. In particular, the behavior of the cube average radius of the dispersion and the variation of the drop size distribution a few minutes after the preparation of the emulsion are described.

Motivation & Objective

• To investigate the impact of interfacial forces and initial droplet size distribution on Ostwald ripening in nanoemulsions.
• To extend the Emulsion Stability Simulation (ESS) framework to include Ostwald ripening dynamics.
• To analyze the time evolution of the cube-average radius in dodecane-in-water emulsions during early-stage stability.
• To evaluate the role of droplet deformability and interfacial interactions in ripening kinetics.
• To provide predictive simulations of droplet size distribution shifts in the first minutes after emulsion preparation.

Proposed method

• Adaptation of the Lifshitz-Slyozov-Wagner (LSW) theory for Ostwald ripening to the ESS framework.
• Incorporation of electrostatic and hydration forces into the ESS potential model to simulate interfacial energy effects.
• Simulation of dodecane-in-water nanoemulsions with varying initial droplet size distributions.
• Modeling of droplet deformability through dynamic shape relaxation in the simulation environment.
• Use of time-dependent tracking of droplet radii to compute the cube-average radius over time.
• Validation of simulation outcomes against theoretical expectations for ripening kinetics.

Experimental results

Research questions

• RQ1 How does the initial droplet size distribution affect the evolution of the cube-average radius in dodecane-in-water nanoemulsions?
• RQ2 To what extent do electrostatic and hydration forces influence Ostwald ripening rates in nanoemulsions?
• RQ3 How does droplet deformability impact the kinetics of droplet coarsening during early-stage emulsion aging?
• RQ4 What are the time-dependent changes in droplet size distribution within the first few minutes after emulsification?
• RQ5 Can the ESS framework accurately predict the growth dynamics of droplets under Ostwald ripening conditions?

Key findings

• The cube-average radius of the dodecane-in-water nanoemulsion increases over time, consistent with Ostwald ripening theory.
• Initial droplet size distributions significantly influence the rate and extent of coarsening in the early stages of emulsion aging.
• Electrostatic and hydration forces were found to modulate interfacial energy, thereby affecting droplet growth kinetics.
• Droplet deformability leads to faster relaxation and altered growth dynamics compared to rigid-sphere models.
• The simulation results show measurable changes in droplet size distribution within minutes after emulsion preparation.
• The extended ESS framework successfully captures the time evolution of the cube-average radius under realistic interfacial force conditions.