Predicting Spontaneous Emulsification in Saltwater Environments Using the HLD Model

Davis, Cole R.; Martínez, Carlos; Howarter, John A.; Erk, Kendra A.

doi:10.1021/acs.langmuir.1c01277

Cited by 9 publications

(30 citation statements)

References 50 publications

(135 reference statements)

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“…The chemical compositions and conditions used to produce spontaneous emulsions have been largely trial and error until recently. 26 This work provides further development of the HLD model as a practical way to guide what salinity, surfactant composition, and oil type create the conditions favorable (unfavorable) to promote (prevent) spontaneous emulsification. HLD mix calculations agreed well with the experimental results in this study.…”

Section: ■ Conclusionmentioning

confidence: 97%

“…A similar threshold in HLD mix was previously observed for spontaneous emulsion formation. 26 • The spontaneity increased in both oil and aqueous phases when the HLD mix approached 0. With a negative HLD mix , the spontaneity in the aqueous phase (forming o/w emulsion) was always greater than that in the oil phase (forming w/o emulsion) and vice versa.…”

Section: ■ Conclusionmentioning

confidence: 98%

“…Instead of HLB, the hydrophilic−lipophilic difference (HLD) model can be used to better predict the spontaneity and emulsion phase behavior by taking the surfactant structure, salinity, oil type, and temperature into consideration. 26,28 The HLD model has been widely used in predicting microemulsion behavior. 12 Microemulsions and spontaneous emulsions have different characteristics such as stability, droplet size, and surfactant concentration.…”

Section: ■ Introductionmentioning

confidence: 99%

“…When the HLD approached 0 by increasing the salinity, the spontaneity, including the amount of emulsified oil and emulsification rate, increased. 26 In this study, we built on the work by Davis et al and studied spontaneous emulsification in different systems with different values of HLD mix . The spontaneity mentioned in this work accounts for both the rate of the emulsification process and the turbidity of the oil/aqueous phase.…”

Section: ■ Introductionmentioning

confidence: 99%

“…This method has also been described in detail in previous studies from our group. 26,59 ■ RESULTS AND DISCUSSION Influence of Surfactant Ratio on Spontaneous Emulsification. For systems with two surfactants, HLD mix depends on the ratio of those surfactants.…”

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confidence: 99%

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Spontaneous Emulsions: Adjusting Spontaneity and Phase Behavior by Hydrophilic–Lipophilic Difference-Guided Surfactant, Salt, and Oil Selection

et al. 2022

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Spontaneous emulsion behavior has been difficult to predict and could be influenced by many variables including salinity, temperature, and chemical composition of the oil and surfactant. In this work, the hydrophilic–lipophilic difference (HLD) framework was used to predict the formation of spontaneous emulsions using a mixture of Span-80 and SLES surfactants. The spontaneity and emulsion behavior of different systems were modeled by estimating the HLDmix. The influence of surfactant ratio, salinity, and oil type was investigated. Spontaneous emulsification could only be observed when the HLDmix was between −0.96 and 1.04. Within this range, a negative HLDmix resulted in a greater spontaneity to form o/w emulsion, and a w/o emulsion was more likely to form when the HLDmix was positive. When the HLDmix was close to 0 (between −0.22 and 0.56 in our systems), emulsions were formed in both the oil and aqueous phases with high spontaneity. A combined effect of ultralow interfacial tension, Span-80 micelle swelling, and interfacial turbulence due to Marangoni effects is likely the main mechanism of the spontaneous emulsification observed in this study. A synergistic reduction in interfacial tension was observed between Span-80 and SLES (<1 mN/m). When the HLD of the system was close to 0, a bicontinuous emulsion phase was formed at the oil–water interface. The bicontinuous emulsion broke-up over time due to the ultralow interfacial tension and interfacial turbulence, forming dispersed oil and water droplets. Results from this work provide a practical method to suggest what surfactant composition, salinity, and oil type could promote (or eliminate) the conditions favorable for spontaneous emulsification.

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Section: ■ Conclusionmentioning

confidence: 97%

Section: ■ Conclusionmentioning

confidence: 98%