Surfactant-induced wetting transitions: Role of surface hydrophobicity and effect on oil permeability of ultrafiltration membranes

Keurentjes, J.T.F.; Stuart, M.A. Cohen; Brinkman, Dine; Schroën, C.G.P.H.; Riet, K. van ’t

doi:10.1016/0166-6622(90)80141-p

Cited by 32 publications

(17 citation statements)

References 28 publications

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“…Therefore, there is no substantial adsorption of carboxylates on the paraffin wax, which accounts for little changes in contact angles over the surfactant concentration range studied. The above explanation appears to agree with Keurentjes et al (37) who reported that there was a narrow region of hydrophobicity in which virtually no adsorption of surfactants occurred.…”

Section: Effect Of Surfactant Additionsupporting

confidence: 84%

“…This orientation is dictated by the competition of hydrophobic interaction with electrostatic interaction between the surfactant and the substrate, and is influenced by the structure of both the surfactant and the substrate, as well as the degree of hydrophobicity of the substrate (37,38). For a strongly hydrophobic surface, it is usually accepted that the hydrocarbon chain of surfactant faces the surface, leaving the polar group exposed to water, and thus causing a reduction in contact angle.…”

Section: Effect Of Surfactant Additionmentioning

confidence: 99%

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Interaction of Ionic Species and Fine Solids with a Low Energy Hydrophobic Surface from Contact Angle Measurement

Zhou

Hussein

et al. 1998

Journal of Colloid and Interface Science

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Section: Effect Of Surfactant Additionsupporting

confidence: 84%

Section: Effect Of Surfactant Additionmentioning

confidence: 99%

Interaction of Ionic Species and Fine Solids with a Low Energy Hydrophobic Surface from Contact Angle Measurement

Zhou

Hussein

et al. 1998

Journal of Colloid and Interface Science

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“…These are relatively low speeds compared to the studies undertaken by G. K. Auernhammer and his colleagues [21][22][23][24], where dynamic receding contact angle measurements showed a decrease with increasing velocity as well as with increasing surfactant concentrations. It was postulated in [19][20][21][22] that Marangoni stresses were the main contribution to the contact angle shift. These stresses occur due to local surface tension gradients formed close to the three-phase contact line.…”

Section: Dynamic Contact Anglesmentioning

confidence: 99%

“…Drops deposited on the surface were surrounded by an immiscible liquid with, or without, the presence of surfactant [18,19]. The presence of amphiphilic molecules in a solution affects the wettability of a surface in contact with the solution [20].…”

Section: Introductionmentioning

confidence: 99%

Membrane emulsification: Formation of water in oil emulsions using a hydrophilic membrane

Silva

Starov

Holdich

2017

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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It is shown that formation of water based droplets in an immiscible (i.e. oil) continuous phase can be achieved using a hydrophilic porous metal membrane without prior hydrophobic treatment of the membrane surface. This avoids the need for "health and safety approval" of typical hydrophobic treatments for the membrane, which often use chemicals incompatible with pharma or food applications. To investigate this, wetting experiments were carried out:sessile droplets were used to determine static contact angles and a rotating drum system was used to determine contact angles under dynamic conditions. In the latter case the three-phase contact line was observed between the rotating drum, water and the continuous phase used in the emulsification process; a surfactant was present in the continuous phase which, in this process, has a double function: to assist the wetting of the membrane by the continuous phase, and not the disperse phase, and to stabilize the droplets formed at the surface of the porous membrane during membrane emulsification. KeywordsMembrane surface, hydrophilic, water in oil emulsion, polyvinyl alcohol (PVA), droplets and contact angle 2

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“…Lin et al [17] and Churaev [18] noted that the existence of a thin water precursor film in contact with the leading edge of the droplet plays a significant role. Keurentjes et al [19] stated that surfactants adsorbed onto a hydrophobic surface expose their polar head groups to the solution, whereas in the case of a more hydrophilic surface, surfactant molecule bilayers might form, rendering the surface more hydrophilic. Moreover, Zhang and Han [20] and Rafaï et al [21] noted that spreading was driven by capillary forces dominated by Marangoni forces with a spreading exponent n above 0.25.…”

Section: Introductionmentioning

confidence: 99%

A gemini-type superspreader: Synthesis, spreading behavior and superspreading mechanism

Lin

Wang

Bai

et al. 2017

Chemical Engineering Journal

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Please cite this article as: A gemini-type superspreader: synthesis, spreading behavior and superspreading mechanism, Chemical Engineering Journal (2016), doi: http://dx.doi.org/10. 1016/j.cej.2016.12.132 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. ABSTRACTThis paper describes the facile microwave-assisted synthesis of a series of trisiloxane gemini superspreaders, as well as their surface and aggregation properties and superspreading behavior on plant leaf surfaces. The molecular structures of the trisiloxane gemini surfactants were characterized by Fourier transform infrared spectroscopy (FTIR) and 1 H nuclear magnetic resonance spectroscopy ( 1 H NMR). The obtained thermodynamic parameters showed that an increase in the spacer group (CH 2 ) resulted in decreases in the critical aggregation concentration (CAC), corresponding surface tension (γ CAC ), and surface excess concentration (Γ max ) but increases in the occupied area per surfactant molecule (A CAC ) and absolute values of the standard free energies of aggregation (△G θ mic ) and adsorption (△G θ ads ). An increase in ethoxy units (CH 2 -CH 2 -O-) resulted in increases in the CAC, γ CAC , and A CAC but decreases in Г max and the absolute values of △G θ mic and △G θ ads . The transmission electron microscopy and dynamic light scattering results showed that the average sizes of the aggregates of superspreader solutions increased with an increasing number of spacer units (CH 2 ) but decreased with an increasing number of ethoxy units (CH 2 -CH 2 -O-). The dynamic spreading behavior results demonstrated that the average spreading velocity increased with increasing spacer chain length, and the dependence of the maximum spreading velocity on the ethoxy chain length was nonmonotonous with a maximum at n(EO) = 8.68. The optimal HLB value was essential to obtaining good superspreading behavior, and the substrate wettability (hydrophobic rice plant and hydrophilic mango plant surfaces) greatly influenced the superspreading. The synergistic effects from the precursor film and Marangoni effect existed in the proposed superspreading model.

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Surfactant-induced wetting transitions: Role of surface hydrophobicity and effect on oil permeability of ultrafiltration membranes

Cited by 32 publications

References 28 publications

Interaction of Ionic Species and Fine Solids with a Low Energy Hydrophobic Surface from Contact Angle Measurement

Interaction of Ionic Species and Fine Solids with a Low Energy Hydrophobic Surface from Contact Angle Measurement

Membrane emulsification: Formation of water in oil emulsions using a hydrophilic membrane

A gemini-type superspreader: Synthesis, spreading behavior and superspreading mechanism

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