Charge-driven interfacial gelation of cellulose nanofibrils across the water/oil interface

Vincenzo Calabrese, Marcelo da Silva, Julien Schmitt, Zakir Hossain, Janet L. Scott, Karen Edler

Research output: Contribution to conferencePoster

Abstract

Understanding the assembly of cellulose nanoparticles at water/oil (W/O) interfaces, underpins the use of these easily prepared biobased particles in formulated products. In this study we investigate the spontaneous adsorption of oxidised cellulose nanofibrils (OCNF) across planar W/O interfaces under conditions where bulk contributions are negligible, allowing exploration of
the interfacial phenomena alone. Spontaneous adsorption of the water-dispersible OCNF across the W/O interface was induced by employing an oppositely-charged oil-soluble surfactant. This approach relies on the use of two immiscible liquids as scaffolds, delivering two oppositely-charged species and directing a charge-driven complexation across the W/O interface. Interfacial
rheology experiments showed that, upon complexation of OCNF and the oppositely charged surfactant, interfacial gels were produced, and different interfacial properties obtained by modulating the ζ-potential of the OCNF (by electrolyte addition). 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. Contrarily, 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 (Figure 1). The development of interfacial gels has implications for capsule formation and tuning in O/W emulsions – systems where interfacial rheology studies are extremely challenging, yet where tuneability is key to utility.
Original languageEnglish
Pages32-32
Number of pages1
Publication statusPublished - 2 Sep 2019
Event 33rd Conference of the European Colloid and Interface Society - KU Leuven, Leuven, Belgium
Duration: 8 Sep 201913 Sep 2019
https://kuleuvencongres.be/ecis2019/

Conference

Conference 33rd Conference of the European Colloid and Interface Society
Abbreviated titleECIS 2019
CountryBelgium
CityLeuven
Period8/09/1913/09/19
Internet address

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