Super-Hydrophobicity of Polyester Fabrics Driven by Functional Sustainable Fluorine-Free Silane-Based Coatings

Abstract

Polyester fibers are widely employed in a multitude of sectors and applications from the technical textiles to everyday life thanks to their durability, strength, and flexibility. Despite these advantages, polyester lacks in dyeability, adhesion of coating, hydrophilicity, and it is characterized by a low wettability respect to natural fibers. On this regard, beyond the harmful hydrophobic textile finishings of polyester fabrics containing fluorine-compounds, and in order to avoid pre-treatments, such as laser irradiation to improve their surface properties, research is moving towards the development of fluorine-free and safer coatings. In this work, the (3-glycidyloxypropyl)trimethoxysilane (GPTMS) and various long alkyl-chain alkoxysilanes were employed for the fabrication in the presence of a catalyst of a water-based superhydrophobic finishing for polyester fabrics with a simple sol-gel, non-fluorinated, sustainable approach and the dip-pad-dry-cure method. The finished polyester fabrics surface properties were investigated by static and dynamic water repellency tests. Additionally, the resistance to common water-based liquids, abrasion resistance, moisture adsorption, and air permeability measurements were performed. Scanning electron microscopy was employed to examine the micro- and nano-morphology of the functionalized polyester fabrics surfaces. The obtained superhydrophobic finishings displayed high water-based stain resistance as well as good hydrophobicity after different cycles of abrasion.

Synthesis of a water-based TEOS–PDMS sol–gel coating for hydrophobic cotton and polyester fabrics

“…53 Moreover, the smoother and less readily absorbing water property of polyester surfaces may lead to lower adhesion of the coating. 54,55…”

“…53 Moreover, smoother and more hydrophobic surfaces of polyester may result in lower adhesion of the coating. 54,55 In the temperature test (Fig. 7), the mean WCA values for polyester initially increase as the temperature rises from 30 °C to 120 °C (128.48° to 136.59°), followed by a decline at higher temperatures.…”

“…53 Moreover, the smoother and less readily absorbing water property of polyester surfaces may lead to lower adhesion of the coating. 54,55 Fig. 3 FTIR analysis of the TEOS, PDMS, hydrolysed TEOS and final TEOS-PDMS coating solution.…”

“…The slight decrease in WCA values observed throughout the test can be attributed to the removal of a thin outer layer of the coating due to the mechanical friction caused by the sandpaper. 20,55 However, the underlying coating remained intact, enabling the fabrics to maintain their hydrophobic properties. This suggests the good adhesion of the coating to the fabric surface.…”

Sustainable Secondary-Raw Materials, Natural Substances and Eco-Friendly Nanomaterial-Based Approaches for Improved Surface Performances: An Overview of What They Are and How They Work

“…The ECHA committees most recently proposed restricting the use of particular perfluoroalkyl compounds (PFAS) in certain application sectors [ 155 ]. As a result, examples of environmentally friendly, fluorine-free textile finishings with stain- and water-repellent properties are also documented [ 156 , 157 , 158 ].…”