  Concentrated fabric conditioners are water-based formulations containing 10
wt. % of cationic surfactants that are deposited on textile fibers during the
rinse cycle in a washing machine to make them smoother and softer to touch. In
topical formulations, the concentration of cationic surfactants is reduced by
half, this reduction being compensated by the addition of environment-friendly
polysaccharides. Using atomic force microscopy (AFM), quartz crystal
microbalance with dissipation (QCM-D) and ellipsometry, the deposition of
formulations with or without polysaccharides on model cellulose substrates is
studied. We found that 180 nm long cellulose nanocrystals (CNCs) deposited by
spin-coating on amorphous silicon dioxide or on quartz crystal sensors provide
a good model of cellulose surfaces. QCM-D results reveal strong electrostatic
interactions of the surfactant vesicles and polysaccharides with the CNC layer.
In the presence of polysaccharides, the adsorbed quantities are less (by 60%)
than the sum of the respective amounts of each component, the structure of the
interface being however more homogenous and rigid. This outcome suggests that
surface techniques coupled with CNC coated substrates are promising for
studying interactions of current formulations with cellulose surfaces.
