CO2-responsive O/W microemulsions prepared using a switchable superamphiphile assembled by electrostatic interactions

Chen, Xiangyu; Ma, Xinrui; Yan, Chao; D, Sun; Yeung, Tony; Xu, Zhenghe

doi:10.1016/j.jcis.2018.09.029

Cited by 51 publications

(28 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Namely, the higher the content of amphisolvent is, the easier the formation of a single phase is. Similar phenomena are also discovered in other SFME systems. , …”

Section: Resultssupporting

confidence: 85%

“…Similar phenomena are also discovered in other SFME systems. 25,27 Upon comparison, it is evident that the area of the singlephase region in octanol−DMEA−water is the largest, as high as 47.76% of the total area (Figure 1A). In contrast, the areas of a single-phase region for octanol−MDEA−water and octanol−TEA−water are 32.78 and 18.98% of the total area (Figure 1B, C), respectively.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…To date, some stimuli including light, − magnetic fields, , pH, , CO 2, − redox, and temperature , have been used to trigger MEs, but the reports about stimuli-responsive MEs, especially SFMEs, are still very limited. Furthermore, to the best of our knowledge, these stimuli-responsive MEs can only respond to one stimulus, not to two or more stimuli.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

CO₂ and Temperature Control over Nanoaggregates in Surfactant-Free Microemulsion

Zhou

et al. 2021

Langmuir

View full text Add to dashboard Cite

Smart microemulsions (MEs) recently have attracted significant interests. However, MEs, especially surfactantfree MEs (SFMEs) that respond to more than one stimulus, are rarely reported to date. Here, we reported the first example of dualresponsive SFME in which a CO 2 -sensitive hydroxyethylamine was used as an amphisolvent. This SFME was investigated utilizing ternary phase diagram, dynamic light scattering, and UV−visible spectrum techniques. It was found that three hydroxyethylamines could stabilize the octanol−water mixture to form transparent and isotropic SFMEs including nanoaggregates-rich pre-ouzo zone, regardless of the number of the hydroxyl group. Among them, 2-(dimethyl amino) ethanol (DMEA)-based SFME possesses the largest single-phase region and most sensitive to CO 2 and the changes in temperature. With bubbling of CO 2 /N 2 or decreasing/increasing temperature, both the single-phase region and pre-ouzo zone reversibly shrink and expand, as well as with breathing. However, CO 2 /N 2 -induced change is more significant than that induced by temperature. The former is mainly ascribed to the reversible protonation and deprotonation of DMEA, while the latter is generally interpreted as the effects of temperature on hydrogen bond interaction. Note that CO 2 leads to a thorough demusification from Winsor IV ME to oil-rich and water-rich two phases without nanoaggregates, while cooling only causes to a particular phase separation, producing two new MEs phases, not typical Winsor I or II MEs. Such a unique dual-responsive SFME can not only be applied in the remediation of contaminated soil, drug delivery, and nanoparticles preparation but also opens a new door to switchable emulsion.

show abstract

“…Namely, the higher the content of amphisolvent is, the easier the formation of a single phase is. Similar phenomena are also discovered in other SFME systems. , …”

Section: Resultssupporting

confidence: 85%

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

CO₂ and Temperature Control over Nanoaggregates in Surfactant-Free Microemulsion

Zhou

et al. 2021

Langmuir

View full text Add to dashboard Cite

show abstract

“…Compared with general emulsions, switching MEs may be more difficult because of the high thermodynamic stability. To the best of our knowledge, various stimuli including pH, redox, CO 2 , − magnetic fields, , and light , have been used as a trigger to switch MEs. By contrast, the temperature stimulus not only is free of contamination as well as light and magnet field stimuli but also is easily achieved both in the laboratory and in pH-stimulus industries.…”

Section: Introductionmentioning

confidence: 99%

Temperature-Switchable Surfactant-Free Microemulsion

et al. 2020

View full text Add to dashboard Cite

Stimuli-responsive microemulsions have recently attracted significant interest due to their unique properties. Here, we developed a novel surfactant-free microemulsion (SFME) in a nontoxic ternary mixture, in which dimethyl sulfoxide (DMSO) was used as an amphisolvent, n-butanol was used as a nonpolar phase, and water was used as a polar phase. The DLS results confirmed the presence of the preouzo zone, and the polarity experiment revealed that the single-phase region can be further divided into oil-in-water, bicontinuous, and water-in-oil subregions. The size of droplets increased upon increasing the water or n-butanol content but decreased with increasing DMSO content. With increasing temperature, the area of the single-phase region increased, accompanied by a decrease in the size of the droplets, and the critical point moved to the corner of n-butanol. No matter in what subregion the formulation was found, decreasing temperature to below the phase-transition temperature (PTT) will induce a transition from monophasic MEs to complete phase separation and vice versa. This is mainly attributed to the effect of temperature on the hydrogen-bond interaction. Ag nanoparticles (Ag NPs) can be prepared above the PTT and facilely separated below PTT. The Ag NPs obtained from the current SFME showed higher catalytic activity than that obtained from a common surfactant-based ME.

show abstract

“…Recently, the responsive microemulsions have more advantages in the field of sustainable development such as sustainable separation of oil and water, compared to the conventional microemulsions. Herein, the research studies on microemulsions with stimulus such as CO 2 , − pH, light, and redox reaction have grown enormously.…”

Section: Introductionmentioning

confidence: 99%

Ionic Liquid-Based Microemulsions with Reversible Microstructures Regulated by CO₂

Wang

Dai

et al. 2019

Langmuir

View full text Add to dashboard Cite

CO2-responsive microemulsions based on ionic liquid 1,1,3,3-tetramethylguanidine-oleic acid (TMG-OA) have been designed to provide an approach for reducing the volatilization of amine in amine-containing microemulsions effectively and exhibit reversible transitions of microstructures. The ionic liquid TMG-OA was prepared by the direct neutralization of oleic acid (HOA) and 1,1,3,3-tetramethylguanidine (TMG, one of volatile and toxic amines). From the investigations of nuclear magnetic resonance hydrogen spectrum, pH, thermogravimetry, and automatic interface tension meter, the excellent properties of switchability, stability, and surface activity of TMG-OA were demonstrated, and then the ionic liquid-based microemulsions with CO2 response were prepared with TMG-OA (surfactant), HOA (oil phase), isopropyl alcohol (IPA, cosurfactant), and water. Interestingly, for microemulsions with a higher IPA content (47.42, 44.48 wt %), sizes of microemulsions are increased upon introducing CO2 and decreased upon addition of N2/65 °C. In addition, for microemulsions with a lower IPA content (26.22 wt %), the new microemulsions with different sizes are regenerated after the phase separation of emulsions generated by introducing CO2, and incomplete recovery of microemulsions can be observed upon addition of N2/65 °C. The reversible microstructures are induced by the swelling behavior and the reduced single phase area, which are caused by the reversible conversion between TMG-OA and HOA components.

show abstract

CO2-responsive O/W microemulsions prepared using a switchable superamphiphile assembled by electrostatic interactions

Cited by 51 publications

References 42 publications

CO₂ and Temperature Control over Nanoaggregates in Surfactant-Free Microemulsion

CO₂ and Temperature Control over Nanoaggregates in Surfactant-Free Microemulsion

Temperature-Switchable Surfactant-Free Microemulsion

Ionic Liquid-Based Microemulsions with Reversible Microstructures Regulated by CO₂

Contact Info

Product

Resources

About

CO2-responsive O/W microemulsions prepared using a switchable superamphiphile assembled by electrostatic interactions

Cited by 51 publications

References 42 publications

CO2 and Temperature Control over Nanoaggregates in Surfactant-Free Microemulsion

CO2 and Temperature Control over Nanoaggregates in Surfactant-Free Microemulsion

Temperature-Switchable Surfactant-Free Microemulsion

Ionic Liquid-Based Microemulsions with Reversible Microstructures Regulated by CO2

Contact Info

Product

Resources

About

CO₂ and Temperature Control over Nanoaggregates in Surfactant-Free Microemulsion

CO₂ and Temperature Control over Nanoaggregates in Surfactant-Free Microemulsion

Ionic Liquid-Based Microemulsions with Reversible Microstructures Regulated by CO₂