Sol-gel based halloysite nanotubes functionalized with methyl red for durable colored polyester fabrics

In recent years, there has been growing interest in exploring inorganic fillers and sol-gel technologies as safer alternatives to harmful chemicals traditionally used in textile finishing processes.1 Specifically, the attention has turned towards halloysite nanotubes (HNTs) due to their unique properties and potential applications in material sciences and nanotechnologies. With their distinctive characteristics such as higher length-to-diameter ratio, lower hydroxyl density, and stronger charge distribution on the outer surface, HNTs offer improved dispersion within polymer matrices compared to other nanoparticles. This study focuses on developing sol-gel-based hybrid finishes incorporating functional HNT nanofillers to enhance the technical properties of synthetic fabrics like polyester when applied to textiles. The study explores the interaction between the alkoxysilane precursor (GPTMS), HNT nanofiller, and polyester fabric, either with or without a pH-sensitive dye (methyl red, MR).2 A functionalized methyl red (MR-GPTMS) coating was created in the presence of HNT to effectively anchor the dye onto the fabric, potentially reducing dye leaching seen in conventional dyeing processes. By establishing a covalent bond between the silica sol and the pH-indicator molecule through a coupling agent, the color fading process can be minimized. Spectroscopic analyses using UV-Vis, FT-IR, and NMR techniques were employed to study the chemical structure of the nanosols involved in the process. Additionally, SEM and AFM analyses revealed that the treatment with GPTMSbased sols successfully altered the microstructure of the fabric fibers, resulting in the formation of uniform and durable functional coatings on polyester fibers.