Pickering emulsions are dispersed systems where two immiscible liquids are stabilized by colloidal solid particles. Cellulosic nanocrystals (CNC) and nanofibrillated cellulose (NFC) are both known to stabilize oil-water interfaces despite being non-surface active nanoparticles. In this work, we study the emulsion’s characteristics and properties as a function of particle size, shape and surface chemistry in order to produce controlled micro- and nano-emulsions stabilized by nanocelluloses. For this purpose, four nanocelluloses were investigated; CNCs produced in the laboratory from cotton and industrial CNCs produced from wood are compared to two kinds of NFCs produced from wood pulp, one by enzymatic hydrolysis and the other by TEMPO oxidation. Droplet size distribution, organization of nanoparticles at the interface and mechanical properties were studied. It is here demonstrated that the different types of nanocelluloses investigated are able to produce ultrastable Pickering emulsion. However, it illustrates that a large range of various structures can be obtained according to the shape, driven by the source of nanocellulose, and the process conditions, mainly shear and concentration. Consequently, various emulsion characteristics might be reached taking into account the targeted properties. The resulting Pickering emulsions can serve as templates for various materials. As an example, freeze dried TEMPO NFC stabilized Pickering emulsions have excellent characteristics to form strong porous aerogels with thermal superinsulating properties.

Control of Pickering emulsion properties by the structural characteristics of nanocelluloses

255th National Meeting (2018)

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