In situ synthesis of gold nanoparticles using fique natural fibers as template

Gold nanoparticles were synthesized on the surface of natural fique fibers extracted from the leaves of Furcraea spp., a plant native to the Andean mountains in Colombia. Fique fibers have a low density, are biodegradable, flexible, highly resistant to wear and exhibit excellent thermal degradation making them promising materials for the textile and packing industries as well as fillers for fiber-reinforced composites. Fique fiber surface was rendered positive using a cationizing agent 3-chloro-2-hydroxypropyl trimethyl ammonium chloride (CHTAC) under strong alkaline conditions. Cationic fique fibers were impregnated with an anionic gold complex that was further reduced to generate gold nanoparticles onto the fibers surface. The influence of CHTAC reaction times and NaOH:CHTAC molar ratios were examined. It was found that increasing the NaOH:CHTAC molar ratio had a negligible effect on nanoparticle size, while the surface coverage density was positively influenced. We hypothesize that the number of positive charges on the fiber surface is the key factor behind this observation. UV-Vis diffuse reflectance spectroscopy; mechanical tests and field emission scanning electron microscopy were used to characterize the modified fibers and the resulting nanoparticles. The proposed method opens a new path for the development of functional natural renewable substrates.