Structure of Nanofibrillated Cellulose Monolayers at the Oil/Water Interface

摘要

Surface modified nanofibrillated cellulose (hydrophobized by silylation) has been successfully used as stabilizer for water-in-oil emulsions. It is important to understand the nature of the hydrophobized nanofibrillated cellulose layers at the oil/water (o/w) interface in view of their excellent ability to stabilize emulsions. The hypothesis is that the nanofibrils form a strong network, leading to prevention of coalescence of the water droplets in the oil. Therefore, we have evaluated how the hydrophobized nanofibrils distribute at the o/w interface by studying layers of well characterized nanofibrillated cellulose, prepared by the Langmuir-Blodgett deposition technique. The layer structures were assessed using Atomic Force Microscopy (AFM), Field-Emission Scanning Electron Microscopy (FE-SEM) and image analysis. The results show that nanofibrillated cellulose may occur as single, dispersed fibrils as well as in networks. We conclude that it is likely that the network formation is the main mechanism by which the fibrils prevent coalescence of the emulsion droplets.