Viscoelastic interfaces comprising of cellulose nanocrystals and lauroyl ethyl arginate for enhanced foam stability. Issue 16 (6th April 2020)

• Record Type: Journal Article
• Authors: Czakaj, Agnieszka; Kannan, Aadithya; Wiśniewska, Agnieszka; Grześ, Gabriela; Krzan, Marcel; Warszyński, Piotr; Fuller, Gerald G.
• Is Part Of: Soft matter. Volume 16:Issue 16(2020)
• Page Start: 3981
• Page End: 3990
• Publication Date: 2020-04-06
• Subjects: Soft condensed matter -- Periodicals; 530.413
• DOI: 10.1039/c9sm02392e
• Languages: English
• ISSNs: 1744-683X

Abstract

Abstract : At submillimolar concentrations of lauroyl ethyl arginate, cellulose nanocrystals aggregate and form elongated fibres. This interfacial assembly efficiently stabilises foams. 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.