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Aroma chemicals with vapor pressure in the range of 10 -7460 mPa were applied onto cotton and poly-(ethylene terephthalate) (PET) fabrics. Retentions on these two fabric substrates were measured using gas chromatography/mass spectrometry (GC/MS), while distribution on and within fiber was graphically demonstrated by backscattered electron microscopy (BSE). Aroma chemicals with low vapor pressures were retained on the fabrics to a larger extent than aroma chemicals with higher vapor pressures. Larger amounts of aroma chemicals were retained on cotton than on PET. Effect of fiber type on retention was largest for aroma chemicals with higher vapor pressures; for example, 20% of allyl cyclohexyl propionate (1360 mPa) was retained on cotton fabric after 480 min, while none was detected on PET as compared to ambrettolide (30 mPa) that had no difference between cotton and PET after 480 min.

The adsorption of aroma chemicals on cotton fabric was studied relative to the surfactant concentration, surfactant type, water solubility, and fiber morphology. The adsorption increased with increasing surfactant concentration to a maximum near the critical micelle concentration, then decreased with further increases in surfactant concentration. The adsorption also was found to be highly dependent on the fiber surface area and pore structure; dramatic differences were observed between untreated and mercerized cotton fabric and are believed to be due to morphological differences. Cationic and anionic surfactants increased the aroma chemical adsorption, which varied with surfactant type, with cetyltrimethylammonium chloride (CTAC) > sodium dodecyl sulfate (SDS) > H 2 O. Water solubility also influenced adsorption; in most cases, adsorption increased with water solubility. In addition, adsorption was also influenced by chemical structure and hydrophobic interactions. The adsorption of aroma chemicals on cotton fabric can be attributed to the aqueous solution being physically held in capillaries and pore structures within the fibular structure of cotton fiber and also to molecular interactions among the aroma chemical molecules, surfactants, and cotton substrate.Paper no. S1495 in JSD 8, 311-317 (October 2005).KEY WORDS: Adsorption, aroma chemical, cetyltrimethylammonium chloride, cotton fabric, sodium dodecyl sulfate.The adsorption of aroma chemicals from aqueous surfactant solutions on cotton fibers is of practical importance for understanding the deposition of fragrances during the laundering process. In the laundry process, surfactants are used to remove soils while simultaneously transferring aroma chemicals to the fabric. Subsequently, aroma chemicals are released during the drying, storage, and wearing stages. The deposition and retention of aroma chemicals continue to be a challenge when creating fragrances for fabric care. Escher and Oliveros (1) measured the affinity of aroma chemicals from standard fabric softener and detergent solutions for both cotton and polyacrylonitrile fabrics. They found that the logarithm of these affinities increased linearly with the logarithm of the octanol-and water-partition coefficients, measures of hydrophobicity. Similarly, Espinosa-Jimenez and GimenezMartin (2) found that sorption of cationic surfactants on fibers was influenced by the hydrophobic attraction between a fiber and the hydrophobic portion of the surfactant. Using inverse gas chromatography (GC), Reutenauer and Thielmann (3) measured the specific and dispersive free energies of interaction for aroma chemicals on cotton fabric. Their findings suggest that aroma chemical adsorption is influenced by polar forces such as hydrogen bonding. For example, the heat of sorption for amyl acetate was significantly greater than that of limonene; these authors explained this result by the fact that amyl acetate is more polar and hydrophilic than limonene (4). The adsorption of aroma chemicals differs with fiber type, with c...

When polyelectrolytes are mixed with oppositely charged surfactants at a 1:1 charge ratio, long-range ordered polyelectrolyte−surfactant complexes are formed. In this paper we demonstrate that by using the “Luzzati method” combined with osmotic stress measurements, we were able to determine the polyelectrolyte−surfactant free energy change while transitioning from a Pm3n cubic phase to a hexagonal phase. Assuming that the major contribution to this energy originates from bending energies associated with the structural rearrangements of the surfactants, we determined the bending modulus of the surfactant inside the complex.