Adsorption of a fabric conditioner on cellulose nanocrystals: Synergistic effects of surfactant vesicles and polysaccharides on softness properties

TL;DR

This study investigates how surfactant vesicles and polysaccharides interact with cellulose nanocrystals in fabric conditioners, revealing synergistic effects that enhance softness properties while reducing surfactant content.

Contribution

It demonstrates the use of cellulose nanocrystals as model surfaces and shows how polysaccharides modify surfactant deposition, providing insights into formulation efficiency and surface interactions.

Findings

Polysaccharides reduce surfactant deposition by 60%.

Interactions are strongly electrostatic, leading to more homogeneous interfaces.

CNCs effectively model cellulose surfaces for interaction studies.

Abstract

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.