Sustainable hydrophobic modification of cotton with rosemary wax extracted by supercritical CO₂ explored through DFT analysis.

The present study focuses on the functionalization of cellulose-based textiles with residual rosemary wax, a by-product of supercritical CO₂ extraction of essential oil. The main objectives of this study were to identify the chemical composition of rosemary wax using FTIR, GC-MS, and HPLC techniques, to optimize its application onto cellulose fabrics, and to evaluate the properties of the treated textiles fabrics. In order to verify the efficacy of the treatment, a series of tests were carried out. These included contact angle measurements, water and air permeability testing, breathability assessment, tensile tests, and color evaluation. The obtained results were promising and showed that the treated fabrics exhibited significant hydrophobicity, with a contact angle exceeding 120°, along with excellent color performance (K/S = 12), good wash and crock fastness and excellent light fastness. Furthermore, an evaluation was conducted to ascertain the durability of the treatment, which revealed that the level of hydrophobicity remained within acceptable limits, reaching a value of 98°. A more in-depth study was conducted using Density Functional Theory (DFT) simulations were conducted to investigate the interactions between rosemary wax and cellobiose. This study revealed strong interactions with significant binding energies of -20.33 kcal/mol with carnosic acid and - 18.33 kcal/mol with apigenin, respectively. These interactions were further substantiated by bond critical point (BCP) analyses. The findings indicate that the use of derived wax in the functionalization of hydrophobic textiles is therefore a smart, successful and sustainable way of being part of the circular economy. This maximizes waste and promotes more eco-friendly practices in the industry.