Charge-driven interfacial gelation of cellulose nanofibrils across the water/oil interface. Issue 2 (13th November 2019)

• Record Type: Journal Article
• Authors: Calabrese, Vincenzo; da Silva, Marcelo A.; Schmitt, Julien; Hossain, Kazi M. Zakir; Scott, Janet L.; Edler, Karen J.
• Is Part Of: Soft matter. Volume 16:Issue 2(2019)
• Page Start: 357
• Page End: 365
• Publication Date: 2019-11-13
• Subjects: Soft condensed matter -- Periodicals; 530.413
• DOI: 10.1039/c9sm01551e
• Languages: English
• ISSNs: 1744-683X

Abstract

Abstract : Interfacial gels, obtained by the interaction of water-dispersible oxidised cellulose nanofibrils (OCNF) and oil-soluble oleylamine (OA), were produced across water/oil (W/O) interfaces and studied using imaging and interfacial rheology. Abstract : Interfacial gels, obtained by the interaction of water-dispersible oxidised cellulose nanofibrils (OCNF) and oil-soluble oleylamine (OA), were produced across water/oil (W/O) interfaces. Surface rheology experiments showed that the complexation relies on the charge coupling between the negatively-charged OCNF and OA. Complexation across the W/O interface was found to be dependent on the ζ -potential of the OCNF (modulated by electrolyte addition), leading to different interfacial properties. Spontaneous OCNF adsorption at the W/O interface occurred for particles with ζ -potential more negative than −30 mV, resulting in the formation of interfacial gels; whilst for particles with ζ -potential of ca. −30 mV, spontaneous adsorption occurred, coupled with augmented interfibrillar interactions, yielding stronger and tougher interfacial gels. On the contrary, charge neutralisation of OCNF ( ζ -potential values more positive than −30 mV) did not allow spontaneous adsorption of OCNF at the W/O interface. In the case of favourable OCNF adsorption, the interfacial gel was found to embed oil-rich droplets – a spontaneous emulsification process.