Effects of Yarn Composition and Knitted Macrostructure on the Functional Properties of Smart Textiles with Optical Functionalities

This study analyses the influence of yarn composition and knitted macrostructure on the structural and functional performance of passive smart knitted fabrics with optical functionalities. Twelve knitted macrostructures were produced using folded composite yarns combining cotton, reflective, and photoluminescent components and different stitch patterns. Thickness, air permeability, and reflectance under UV and visible illumination were experimentally evaluated. The results indicate that knitted macrostructure primarily controls thickness and air permeability, whereas optical response is governed by yarn composition. Variations in stitch pattern enable regulation of air permeability independent of optical behaviour, while UV-responsive yarn components dominate reflectance performance. The findings support independent optimisation of structural and optical properties through combined yarn and macrostructural design.