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
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


Conference 33rd Conference of the European Colloid and Interface Society
Abbreviated titleECIS 2019
Internet address

Cite this

Calabrese, V., da Silva, M., Schmitt, J., Hossain, Z., Scott, J. L., & Edler, K. (2019). Charge-driven interfacial gelation of cellulose nanofibrils across the water/oil interface. 32-32. Poster session presented at 33rd Conference of the European Colloid and Interface Society, Leuven, Belgium.