N,N′-Dimethyl-2,3-dialkylpyrazinium salts as redox-switchable surfactants? Redox, spectral, EPR and surfactant properties

Schmittel, Michael; Lal, Mukul; Graf, Karlheinz; Jeschke, Gunnar; Suske, Irina; Salbeck, Josef

doi:10.1039/b511923e

Cited by 41 publications

(34 citation statements)

References 20 publications

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“…Given that most emulsions and dispersions are stabilized by surfactants, a popular approach in the literature is to use switchable surfactants, meaning a surfactant that can be switched from a dispersion-stabilizing form into a form that does not stabilize dispersions. [1,2] Triggers for published switchable surfactants include addition of acids, [2,3] redox reagents [4] or even UV light. [5] UV light is a less-effective trigger for emulsions or suspensions, especially for large-scale applications, because UV light will decay quickly at long distances or in media with a large refractive index.…”

Section: Introductionmentioning

confidence: 99%

A Conventional Surfactant Becomes CO₂‐Responsive in the Presence of Switchable Water Additives

Robert

Mercer

et al. 2013

Chemistry A European J

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We have developed a new benign means of reversibly breaking emulsions and latexes by using "switchable water", an aqueous solution of switchable ionic strength. The conventional surfactant sodium dodecyl sulfate (SDS) is not normally stimuli-responsive when CO2 is used as the stimulus but becomes CO2 -responsive or "switchable" in the presence of a switchable water additive. In particular, changes in the air/water surface tension and oil/water interfacial tension can be triggered by addition and removal of CO2 . A switchable water additive, N,N-dimethylethanolamine (DMEA), was found to be an effective and efficient additive for the reversible reduction of interfacial tension and can lower the tension of the dodecane/water interface in the presence of SDS surfactant to ultra-low values at very low additive concentrations. Switchable water was successfully used to reversibly break an emulsion containing SDS as surfactant, and dodecane as organic liquid. Also, the addition of CO2 and switchable water can result in aggregation of polystyrene (PS) latexes; the later removal of CO2 neutralizes the DMEA and decreases the ionic strength allowing for the aggregated PS latex to be redispersed and recovered in its original state.

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Section: Introductionmentioning

confidence: 99%

A Conventional Surfactant Becomes CO₂‐Responsive in the Presence of Switchable Water Additives

Robert

Mercer

et al. 2013

Chemistry A European J

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“…[1][2][3][4][5][6][7][8][9][10][11][12][13] As a switchable surfactant can undergo fully reversible interconversions between active and inactive forms, it is possible to recover and re-use the surfactant afterwards and to easily remove it from product streams by switching it to the form that is least soluble in the relevant medium. [1][2][3][4][5][6][7][8][9][10][11][12][13] As a switchable surfactant can undergo fully reversible interconversions between active and inactive forms, it is possible to recover and re-use the surfactant afterwards and to easily remove it from product streams by switching it to the form that is least soluble in the relevant medium.…”

mentioning

confidence: 99%

Switchable Pickering Emulsions Stabilized by Silica Nanoparticles Hydrophobized In Situ with a Switchable Surfactant

Jiang¹,

Zhu²,

Cui³

et al. 2013

Angew Chem Int Ed

176

199

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“…Switchable surfactants offer an alternative control on latex stability 7–12. These molecules have surface activities that could be switched on and off by certain triggers.…”

Section: Introductionmentioning

confidence: 99%

Preparation of CO₂/N₂‐Triggered Reversibly Coagulatable and Redispersible Polyacrylate Latexes by Emulsion Polymerization Using a Polymeric Surfactant

Zhang

Wang

et al. 2012

Macromol. Rapid Commun.

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We report here a novel approach for making reversibly coagulatable and redispersible polyacrylate latexes by emulsion (co)polymerization of methyl methacrylate (MMA) using a polymeric surfactant, poly(2-(dimethylamino)ethyl methacrylate)(10) -block-poly(methyl methacrylate)(14) . The surfactant was protonated with HCl prior to use. The resulted PMMA latexes were readily coagulated with trace amount of caustic soda. The coagulated latex particles, after washing with deionized water, could be redispersed into fresh water to form stable latexes again by CO(2) bubbling with ultrasonication. The recovered latexes could then be coagulated by N(2) bubbling with gentle heating. These coagulation and redispersion processes were repeatable by the CO(2) /N(2) bubbling.

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N,N′-Dimethyl-2,3-dialkylpyrazinium salts as redox-switchable surfactants? Redox, spectral, EPR and surfactant properties

Abstract: N,N'-dimethyl-2,3-dialkylpyrazinium salts show reversible transitions between all redox stages and a monolayer formation at the air-water interface that suggests their use as redox-switchable surfactants.

Cited by 41 publications

References 20 publications

A Conventional Surfactant Becomes CO₂‐Responsive in the Presence of Switchable Water Additives

A Conventional Surfactant Becomes CO₂‐Responsive in the Presence of Switchable Water Additives

Switchable Pickering Emulsions Stabilized by Silica Nanoparticles Hydrophobized In Situ with a Switchable Surfactant

Preparation of CO₂/N₂‐Triggered Reversibly Coagulatable and Redispersible Polyacrylate Latexes by Emulsion Polymerization Using a Polymeric Surfactant

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N,N′-Dimethyl-2,3-dialkylpyrazinium salts as redox-switchable surfactants? Redox, spectral, EPR and surfactant properties

Abstract: N,N'-dimethyl-2,3-dialkylpyrazinium salts show reversible transitions between all redox stages and a monolayer formation at the air-water interface that suggests their use as redox-switchable surfactants.

Cited by 41 publications

References 20 publications

A Conventional Surfactant Becomes CO2‐Responsive in the Presence of Switchable Water Additives

A Conventional Surfactant Becomes CO2‐Responsive in the Presence of Switchable Water Additives

Switchable Pickering Emulsions Stabilized by Silica Nanoparticles Hydrophobized In Situ with a Switchable Surfactant

Preparation of CO2/N2‐Triggered Reversibly Coagulatable and Redispersible Polyacrylate Latexes by Emulsion Polymerization Using a Polymeric Surfactant

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A Conventional Surfactant Becomes CO₂‐Responsive in the Presence of Switchable Water Additives

A Conventional Surfactant Becomes CO₂‐Responsive in the Presence of Switchable Water Additives

Preparation of CO₂/N₂‐Triggered Reversibly Coagulatable and Redispersible Polyacrylate Latexes by Emulsion Polymerization Using a Polymeric Surfactant