Surfactant-mediated interaction of fragrances with cellulose model surfaces

Odor perception may be considered from different perspectives: the physicochemical properties of odorants and target surfaces of interest, the biological aspects of electing odorant molecules by odorant receptors and their related downstream cellular signaling, and finally the physiological dimension of the sensing individual. This work concentrates on physico-chemical investigations, with the objective of developing novel analytical approaches to study in real time how odorant molecules together with their surfactant matrix interact with target surfaces of interest. Specifically the work presented in this thesis, deals with perfume-surfactant adsorption on cellulose model layers which should mimic the cotton fibres of fabrics. Surface sensitive attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy has been used to monitor the perfume-surfactant adsorption process. The thesis is structured as follows: The first part concerns the preparation of cellulose model surfaces. Cellulose layers with thicknesses in the range of 50-500 nm have been achieved by first spin coating of trimethysilylcellulose (TMSC) on silicon wafers or ATR-Ge crystals followed by a simple regeneration procedure. Physicochemical characterisation of these layers was performed by different techniques. The second part focuses on surfactant-perfume system. Multilamellar, sonicated and extruded vesicles of cationic surfactant dimethyldioctadecyl-ammonium chloride (DODAC), as commercially used in formulations containing fragrances, were prepared and used to entrap the perfumes. Theses vesicles were characterized by spectroscopic and microscopic techniques. Finally in the last part of this work, the adsorption and desorption kinetics of vesicles and fragrances on cellulose model surfaces are presented. The experiments were performed using an ATR-FTIR flow cell with different DODAC-perfume dispersions. The results obtained for adsorption of perfumes and surfactants to the cellulose model surfaces were compared with experiments performed on real cotton fabric.