Sol-gel derived nano-array structures on plant fibers: Nucleation and growth mechanisms

Nano-arrays deposition has emerged as a powerful strategy for enhancing the surface and mechanical properties of plant fibers. However, there is a lack of in-depth understanding of the underlying relationship between nano-array formation and deposition conditions. In this study, the complex interactions between the surface characteristics of plant fibers and the sol-gel process parameters are elaborated, providing insights into the mechanisms driving in-situ nucleation and growth dynamics of nano-arrays. For the fiber surface, the introduced carboxymethyl groups and the concave morphology facilitate the heterogeneous deposition of nano-arrays by strengthening the interaction between the fibers and the deposited structures, creating ideal deposition sites for the layer-by-layer self-assembly of nano-arrays. In the sol-gel process, the precursor concentration acts as the driving force for heterogeneous nucleation and growth of nano-arrays. The catalyst concentration influences the morphologies of nano-structures, dictating whether thin nano-gels, well-aligned nano-arrays, or aggregated nano-particles. The reaction time determines the nucleation and growth cycles of nano-arrays. In this case, the well-aligned SiO ₂ nano-arrays are deposited on the carboxymethyl pre-treated jute fibers in the ethanol/water solution containing 0.60 mol/L ammonia (catalyst) and 0.08 mol/L TEOS (precursor) for 6 h. Through the grey relational analysis, the influence of these three factors on particle size follows this order: reaction time < precursor concentration < catalyst concentration. The relationship between the surface features of plant fibers and sol-gel parameters enables the formation of well-aligned nano-arrays that effectively repair surface defects, ensuring precise control over the efficient fabrication of plant fibers with significantly enhanced properties.