Estudo fenomenológico da difusão de fragrâncias

Abstract

This study proposes a mathematical method based on an engineering approach to describe the diffusive phenomena associated with fragrances. The first goal was to experimentally validate the evaporation and permeation profiles of fragrance systems applied to the skin, or on surfaces. The proposed model is based on the vapor pressure and the permeability coefficient of the fragrant material, through differential mass balances in each control volume involved in the process. Vapor pressure data at room temperature are scarce and an adequate way to measure them is by thermogravimetric analysis (TG-DTA). For the permeability coefficient, the experimental tests were performed using a Franz diffusion cell with pig skin. A set of fragrances had their permeability coefficients determined by Franz cell diffusion experiments in ethanolic solution. A QSAR model was proposed to correlate the experimental data. Antoine's constants and thermodynamic functions were determined for the same set of materials, in order to describe their low vapor pressures. The differential model described well the release and permeation of all tested fragrance systems. A predictive radial model for diffusion in space and over time was proposed and validated through experiments in a diffusion chamber using the solid phase micro extraction (SPME) technique. Briefly, the work proposes a methodology to predict the performance (diffusion, impact, tenacity and volume) of fragrances from the skin or other surface, promoting the optimization in the development of new fragrance formulations.