Design of eco-friendly fabric softeners: structure, rheology and interaction with cellulose nanocrystals

Abstract

Concentrated fabric softeners are water-based formulations containing around 10 - 15 wt. % of double tailed esterquat surfactants primarily synthesized from palm oil. In recent patents, it was shown that a significant part of the surfactant contained in today formulations can be reduced by circa 50 % and replaced by natural guar polymers without detrimental effects on the deposition and softening performances. We presently study the structure and rheology of these softener formulations and identify the mechanisms at the origin of these effects. The polymer additives used are guar gum polysaccharides, one cationic and one modified through addition of hydroxypropyl groups. Formulations with and without guar polymers are investigated using optical and cryo-transmission electron microscopy, small-angle light and Xray scattering and finally rheology. Similar techniques are applied to study the phase behavior of softener and cellulose nanocrystals considered here as a model for cotton. The esterquat surfactants are shown to assemble into micron-sized vesicles in the dilute and concentrated regimes. In the former, guar addition in small amounts does not impair the vesicular structure and stability. In the concentrated regime, cationic guars induce a local crowding associated to depletion interactions and leads to the formation of a local lamellar order. In rheology, adjusting the polymer concentration at one tenth that of the surfactant is sufficient to offset the decrease of the elastic property associated with the surfactant reduction. In conclusion, we have shown that through an appropriate choice of natural additives it is possible to lower the concentration of surfactants in fabric conditioners by about half, a result that could represent a significant breakthrough in current home care formulations.

10 pages 8 figures

References in corpus (5)

• Stoichiometry of Electrostatic Complexes Determined by Light Scattering
• Biophysicochemical interaction of a clinical pulmonary surfactant with nano-alumina
• Fabric Softener/Cellulose Nanocrystal Interaction: A Model For Assessing Surfactant Deposition On Cotton
• Polyelectrolyte assisted charge titration spectrometry: applications to latex and oxide nanoparticles
• Adsorption and onset of lubrication by a double-chained cationic surfactant on silica surfaces

Cited by in corpus (5)

• Design and applications of a fluorescent labeling technique for lipid and surfactant preformed vesicles
• Cellulose nanocrystals mimicking micron sized fibers to assess the deposition of latex particles on cotton
• Adsorption of a fabric conditioner on cellulose nanocrystals: Synergistic effects of surfactant vesicles and polysaccharides on softness properties
• Advanced eco-friendly formulations of guar biopolymer-based textile conditioners
• Silicone incorporation into an esterquat based fabric softener in presence of guar polymers