Observations and explanations of ejection phenomena in liquid–liquid systems due to interfacial instability

Abstract Unidirectional ejections in binary and ternary liquid–liquid systems within a diffusion cell were linked to diverse molecular motions driven by energy instability (EI). The nature of the ejected streams varied with time. Still, they were similar across different systems, with ejections occurring from the interface's specific portions over extended durations. Some systems exhibited intermittent ejections. One system exhibited interfacial jerking due to the interface's spreading, caused by extremely low interfacial tension. An improved theory of EI was proposed, incorporating the raffinate phase barrier and the viscosities of both the solute and raffinate phases. This theory explains how molecular clusters form mass ejections larger than the molecular diameter by merging molecules having different energies. The theory was also justified by comparing various phenomena across systems. The significance of this work lies in enhancing the understanding of ejection mechanisms and predicting interfacial mass transfer rates, offering valuable insights for various liquid–liquid applications.