(332i) Enhancement of Perfume Deposition from Powder Detergent into Fabrics

Scent is one of the most important factors affecting consumer satisfaction in the fast-moving consumer goods industry. However, the inherent volatile nature and polarity of perfume raw materials (PRMs) in formulated products makes retention of perfume oils into woven substrates challenging and not fully comprehended. A large proportion of these compounds are lost in wastewater during clothes washing cycles (1). Previous studies show that deposition and penetration of PRM can be related to the Weber (We ≡ ρD₀ν²/σ) and Reynold (Re ≡ ρD₀ν/η) numbers, both of which are affected by the interfacial tension between droplets and substrates (2). Where droplet diameter (D₀), surface tension of the liquid (σ), density (ρ), impact velocity (ν), and shear viscosity (η).

By using optical tensiometry, we studied the ability of different surfactants to reduce interfacial tension of PRMs at concentrations of interest, determining which had the largest effect. The study of more droplet properties, such as average droplet size was conducted by using fluorescence labelled PRM to create emulsions that were later deposited into fabrics. Allowing for both determination of size and visual tracking of the droplets through the various fabric substrates of interest. Through this nemethodology, we provide a simple and comprehensive way of predicting droplet deposition onto fabric substrate which we aim to apply into the new generation of detergent products.

Results

1. Interfacial tension

The effect of industrially relevant surfactants on the interfacial tension (IT) between the PRM of interest and water was measured using optical methods such as pendant droplet and buoyant droplet. These studies provide information on the stability of the PRM droplets in the washing solutions which is a key driver for deposition onto fabrics. This information can be linked with recent studies (1,3), where the spreading and wicking of liquid droplets on fabric are related to the interfacial tension between the emulsified droplet and fabrics in the wash environment, as well as parameters including initial droplet size and approaching velocity to the fabric surface. Figure 1 shows that an increased concentration of Surfactant 2 (non-ionic) has negligible effect on the IT of more hydrophilic PRMs (even above critical micelle concentration (CMC)). Surfactant 1 (anionic) consistently reduces IT between hydrophobic and hydrophilic PRMs and water.

1. Effect of PRM mixtures on deposition of fragrance

Fragrances are complex mixtures rather than single-component systems, comprising multiple volatile and semi-volatile compounds. In this study, we investigate how different fragrance mixtures influence the deposition of key perfume raw materials (PRMs) onto fabrics during a simulated washing machine cycle. Using tergotometers, we replicate the mechanical and chemical conditions of a standard wash process to assess the retention and transfer efficiency of PRMs. After washing, the fabrics are carefully extracted to isolate the deposited PRMs, which are subsequently analysed using gas chromatography-mass spectrometry (GC-MS) to quantify and characterise their distribution. This approach provides insights into the role of formulation variables in fragrance deposition and longevity on textiles.

Summary

Several methodologies have been established to investigate the interfacial characteristics of PRM and water as a function of surfactant type and chemistry, which provides the foundation to develop strategies for improving droplet deposition on porous substrates. In parallel, deposition was quantified via GCMS allowing to suggest potential .

References

1. Manga, M., et al. 2022. Deposition and retention of differently shaped micro-particles on textiles during laundry processing. Powder Technology, 398, p.117143.
2. de Goede, T., et al. 2021. Droplet impact of Newtonian fluids and blood on simple fabrics: Effect of fabric pore size and underlying substrate. Physics of Fluids, 33(3), p.033308.
3. Argentou, E., et al. 2022. Modulating the surface and mechanical properties of textile by oil-in-water emulsion design. RSC Advances, 12(4), pp.2160-2170.