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  1. Article ; Online: The Influence of the Surface Chemistry of Cellulose Nanocrystals on Ethyl Lauroyl Arginate Foam Stability.

    Czakaj, Agnieszka / Chatzigiannakis, Emmanouil / Vermant, Jan / Krzan, Marcel / Warszyński, Piotr

    Polymers

    2022  Volume 14, Issue 24

    Abstract: Guanidine-based surfactant ethyl lauroyl arginate (LAE) and cellulose nanocrystals (CNCs) form complexes of enhanced surface activity when compared to pure surfactants. The LAE-CNC mixtures show enhanced foaming properties. The dynamic thin-film balance ... ...

    Abstract Guanidine-based surfactant ethyl lauroyl arginate (LAE) and cellulose nanocrystals (CNCs) form complexes of enhanced surface activity when compared to pure surfactants. The LAE-CNC mixtures show enhanced foaming properties. The dynamic thin-film balance technique (DTFB) was used to study the morphology, drainage and rupture of LAE-CNC thin liquid films under constant driving pressure. A total of three concentrations of surfactant and the corresponding mixtures of LAE with sulfated (sCNC) and carboxylated (cCNC) cellulose nanocrystals were studied. The sCNC and cCNC suspension with LAE formed thin films, with stability increasing with surfactant concentration and with complex rheological properties. In the presence of LAE, the aggregation of CNC was observed. While the sCNC aggregates were preferentially present in the film volume with a small fraction at the surface, the cCNC aggregates, due to their higher hydrophobicity, were preferentially located at film interfaces, forming compact layers. The presence of both types of aggregates decreased the stability of the thin liquid film compared to the one for the LAE solution with the same concentration. The addition of CNC to LAE was critical for foam formation, and foam stability was in qualitative agreement with the thin films' lifetimes. The foam volume increased with the LAE concentration. However, there was an optimum surfactant concentration to achieve stable foam. In particular, the very resistant foam was obtained with cCNC suspensions that formed the interfaces with a complex structure and rheology. On the other hand, at high LAE concentrations, the aggregates of CNC may exhibit antifoaming properties.
    Language English
    Publishing date 2022-12-09
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2527146-5
    ISSN 2073-4360 ; 2073-4360
    ISSN (online) 2073-4360
    ISSN 2073-4360
    DOI 10.3390/polym14245402
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Ethyl Lauroyl Arginate, an Inherently Multicomponent Surfactant System.

    Czakaj, Agnieszka / Jarek, Ewelina / Krzan, Marcel / Warszyński, Piotr

    Molecules (Basel, Switzerland)

    2021  Volume 26, Issue 19

    Abstract: Ethyl lauroyl arginate (LAE) is an amino acid-based cationic surfactant with low toxicity and antimicrobial activity. It is widely used as a food preservative and component for food packaging. When stored, LAE decomposes by hydrolysis into surface-active ...

    Abstract Ethyl lauroyl arginate (LAE) is an amino acid-based cationic surfactant with low toxicity and antimicrobial activity. It is widely used as a food preservative and component for food packaging. When stored, LAE decomposes by hydrolysis into surface-active components Nα-lauroyl-l-arginine (LAS) or dodecanoic (lauric) acid. There are only a limited number of reports considering the mechanism of surface activity of LAE. Thus, we analysed the surface tension isotherm of LAE with analytical standard purity in relation to LAE after prolonged storage. We used quantum mechanical density functional theory (DFT) computations to determine the preferred hydrolysis path and discuss the possibility of forming highly surface-active heterodimers, LAE-dodecanoate anion, or LAE-LAS. Applying molecular dynamics simulations, we determined the stability of those dimers linked by electrostatic interactions and hydrogen bonds. We used the adsorption model of surfactant mixtures to successfully describe the experimental surface tension isotherms. The real part surface dilational modulus determined by the oscillation drop method follows a diffusional transport mechanism. However, the nonlinear response of the surface tension could be observed for LAE concentration close to and above Critical Micelle Concentration (CMC). Nonlinearity originates from the presence of micelles and the reorganisation of the interfacial layer.
    Language English
    Publishing date 2021-09-29
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 1413402-0
    ISSN 1420-3049 ; 1431-5165 ; 1420-3049
    ISSN (online) 1420-3049
    ISSN 1431-5165 ; 1420-3049
    DOI 10.3390/molecules26195894
    Database MEDical Literature Analysis and Retrieval System OnLINE

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    In stock of ZB MED Cologne/Königswinter

    Zs.MO 81: Show issues

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  3. Article ; Online: Surface Properties of Saponin-Chitosan Mixtures.

    Krzan, Marcel / Rey, Natalia García / Jarek, Ewelina / Czakaj, Agnieszka / Santini, Eva / Ravera, Francesca / Liggieri, Libero / Warszynski, Piotr / Braunschweig, Björn

    Molecules (Basel, Switzerland)

    2022  Volume 27, Issue 21

    Abstract: The surface properties of saponin and saponin-chitosan mixtures were analysed as a function of their bulk mixing ratio using vibrational sum-frequency generation (SFG), surface tensiometry and dilational rheology measurements. Our experiments show that ... ...

    Abstract The surface properties of saponin and saponin-chitosan mixtures were analysed as a function of their bulk mixing ratio using vibrational sum-frequency generation (SFG), surface tensiometry and dilational rheology measurements. Our experiments show that saponin-chitosan mixtures present some remarkable properties, such as a strong amphiphilicity of the saponin and high dilational viscoelasticity. We believe this points to the presence of chitosan in the adsorption layer, despite its complete lack of surface activity. We explain this phenomenon by electrostatic interactions between the saponin as an anionic surfactant and chitosan as a polycation, leading to surface-active saponin-chitosan complexes and aggregates. Analysing the SFG intensity of the O-H stretching bands from interfacial water molecules, we found that in the case of pH 3.4 for a mixture consisting of 0.1 g/L saponin and 0.001 g/L chitosan, the adsorption layer was electrically neutral. This conclusion from SFG spectra is corroborated by results from surface tensiometry showing a significant reduction in surface tension and effects on the dilational surface elasticity strictly at saponin/chitosan ratios, where SFG spectra indicate zero net charge at the air-water interface.
    MeSH term(s) Chitosan ; Saponins/chemistry ; Surface Tension ; Surface Properties ; Surface-Active Agents/chemistry ; Adsorption ; Water/chemistry
    Chemical Substances Chitosan (9012-76-4) ; Saponins ; Surface-Active Agents ; Water (059QF0KO0R)
    Language English
    Publishing date 2022-11-03
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 1413402-0
    ISSN 1420-3049 ; 1431-5165 ; 1420-3049
    ISSN (online) 1420-3049
    ISSN 1431-5165 ; 1420-3049
    DOI 10.3390/molecules27217505
    Database MEDical Literature Analysis and Retrieval System OnLINE

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    In stock of ZB MED Cologne/Königswinter

    Zs.MO 81: Show issues

    Order via subito

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  4. Article ; Online: The Influence of the Surface Chemistry of Cellulose Nanocrystals on Ethyl Lauroyl Arginate Foam Stability

    Czakaj, Agnieszka / Chatzigiannakis, Emmanouil / id_orcid:0 000-0001-6474-7662 / Vermant, Jan / Krzan, Marcel / Warszyński, Piotr

    Polymers, 14 (24)

    2022  

    Abstract: Guanidine-based surfactant ethyl lauroyl arginate (LAE) and cellulose nanocrystals (CNCs) form complexes of enhanced surface activity when compared to pure surfactants. The LAE-CNC mixtures show enhanced foaming properties. The dynamic thin-film balance ... ...

    Abstract Guanidine-based surfactant ethyl lauroyl arginate (LAE) and cellulose nanocrystals (CNCs) form complexes of enhanced surface activity when compared to pure surfactants. The LAE-CNC mixtures show enhanced foaming properties. The dynamic thin-film balance technique (DTFB) was used to study the morphology, drainage and rupture of LAE-CNC thin liquid films under constant driving pressure. A total of three concentrations of surfactant and the corresponding mixtures of LAE with sulfated (sCNC) and carboxylated (cCNC) cellulose nanocrystals were studied. The sCNC and cCNC suspension with LAE formed thin films, with stability increasing with surfactant concentration and with complex rheological properties. In the presence of LAE, the aggregation of CNC was observed. While the sCNC aggregates were preferentially present in the film volume with a small fraction at the surface, the cCNC aggregates, due to their higher hydrophobicity, were preferentially located at film interfaces, forming compact layers. The presence of both types of aggregates decreased the stability of the thin liquid film compared to the one for the LAE solution with the same concentration. The addition of CNC to LAE was critical for foam formation, and foam stability was in qualitative agreement with the thin films’ lifetimes. The foam volume increased with the LAE concentration. However, there was an optimum surfactant concentration to achieve stable foam. In particular, the very resistant foam was obtained with cCNC suspensions that formed the interfaces with a complex structure and rheology. On the other hand, at high LAE concentrations, the aggregates of CNC may exhibit antifoaming properties.

    ISSN:2073-4360
    Keywords foam stability ; dynamic thin-film balance ; cellulose nanocrystals ; surface chemistry ; surface tension ; fluid film ; surface dynamics ; interfacial phenomena
    Subject code 600
    Language English
    Publisher MDPI
    Publishing country ch
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  5. Article ; Online: Correction: Viscoelastic interfaces comprising of cellulose nanocrystals and lauroyl ethyl arginate for enhanced foam stability.

    Czakaj, Agnieszka / Kannan, Aadithya / Wiśniewska, Agnieszka / Grześ, Gabriela / Krzan, Marcel / Warszyński, Piotr / Fuller, Gerald G

    Soft matter

    2020  Volume 16, Issue 21, Page(s) 5094

    Abstract: Correction for 'Viscoelastic interfaces comprising of cellulose nanocrystals and lauroyl ethyl arginate for enhanced foam stability' by Agnieszka Czakaj et al., Soft Matter, 2020, 16, 3981-3990, DOI: . ...

    Abstract Correction for 'Viscoelastic interfaces comprising of cellulose nanocrystals and lauroyl ethyl arginate for enhanced foam stability' by Agnieszka Czakaj et al., Soft Matter, 2020, 16, 3981-3990, DOI: .
    Language English
    Publishing date 2020-05-20
    Publishing country England
    Document type Journal Article ; Published Erratum
    ZDB-ID 2191476-X
    ISSN 1744-6848 ; 1744-683X
    ISSN (online) 1744-6848
    ISSN 1744-683X
    DOI 10.1039/d0sm90090g
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Viscoelastic interfaces comprising of cellulose nanocrystals and lauroyl ethyl arginate for enhanced foam stability.

    Czakaj, Agnieszka / Kannan, Aadithya / Wiśniewska, Agnieszka / Grześ, Gabriela / Krzan, Marcel / Warszyński, Piotr / Fuller, Gerald G

    Soft matter

    2020  Volume 16, Issue 16, Page(s) 3981–3990

    Abstract: Stable aqueous foams composed of oppositely charged nanoparticles and surfactants have recently gained attention. We studied the draining of thin liquid films and the foam stability of aqueous mixtures of food grade cellulose nanocrystals (CNCs) and an ... ...

    Abstract Stable aqueous foams composed of oppositely charged nanoparticles and surfactants have recently gained attention. We studied the draining of thin liquid films and the foam stability of aqueous mixtures of food grade cellulose nanocrystals (CNCs) and an oppositely charged surfactant - lauroyl ethyl arginate (LAE). Dynamic fluid film interferometry experiments with the bubble approaching the air/solution interface revealed a two-fold increase of the initial bubble film thickness and a maximum in drainage time at the optimal stoichiometry of LAE and CNC. The temporal evolution of the fluid film shape indicated a large contribution of structural forces to the film stability. The results of single liquid film drainage time and coalescence time experiments were partially correlated with bulk foam stability. With a further increase of LAE concentration, aggregation-induced foam destruction was observed. In the presence of a cationic surfactant, anisotropic and initially hydrophilic cellulose nanocrystals became partially hydrophobized and self-assembled at the interface. Cellulose nanocrystal shape anisotropy and wetting behaviour which have their origins in OH-exposed and buried crystalline planes are the sources of capillary interactions that promote CNC aggregation at planar and curved liquid/air interfaces. Dilatational and shear interfacial rheology experiments confirmed the formation of a highly elastic surfactant-nanoparticle interfacial layer. To the best of our knowledge, this is the first report on foaming properties for this system with fast adsorption kinetics influenced by CNC.
    Language English
    Publishing date 2020-04-06
    Publishing country England
    Document type Journal Article
    ZDB-ID 2191476-X
    ISSN 1744-6848 ; 1744-683X
    ISSN (online) 1744-6848
    ISSN 1744-683X
    DOI 10.1039/c9sm02392e
    Database MEDical Literature Analysis and Retrieval System OnLINE

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