The main working mechanism for stabilization with microfibrillated cellulose (MFC) are thickening and entrapment in the network substructure.
Solid particles like pigments get trapped inside the network structure of MFC which prevents them from settling. The increased viscosity also counteracts the sedimentation due to gravity. These two effects lead to stabilization of suspensions and additionally improve the dispersion of particles.
1% pigment in water
1% pigment + 0.5% MFC in water
The addition of MFC in water in oil emulsions can improve the stability of the formulation, MFC is however not an emulsifier. Apart from thickening the aqueous matrix, depending on their size oil droplets can also get trapped inside the network structure which prevents them from coalescing.