Silica Nanoparticle Deposition on Natural Fibrous Substrates: Kinetic and Thermodynamic Studies

Surface nanofunctionalization of fiber-based substrates has been extensively explored for the fabrication of functional fabrics, but understanding the kinetics and thermodynamics of nanoparticle adsorption on fibers are essential for better control of the process. Herein, we investigated the deposition kinetics and thermodynamic aspects of silica nanoparticles with varied sizes onto the silk fibers. The results show that the deposition of SiO2 nanoparticles on the positively charged fibers depends on the concentration and the deposition time. The deposition kinetics could be well depicted quantitatively using a modified collision model. The small-sized nanoparticles (12, 21, 33, and 58 nm in diameter) have enthalpy-driven interactions, whereas the large-sized nanoparticles (105 nm in diameter) have entropy-driven interactions during the nanofunctionalization, as revealed by the isothermal titration calorimetry experiments. The contribution of hydrogen bonding accounts for approximately 5%-10% of the total binding enthalpy based on the corresponding thermodynamic parameters and the proposed adsorption model.

Automated summary

This study investigates the deposition kinetics and thermodynamic aspects of silica nanoparticles on silk fibers, revealing that the interaction between nanoparticles and fibers is size-dependent and can be quantitatively described using a modified collision model. The small-sized nanoparticles have enthalpy-driven interactions, while the large-sized nanoparticles have entropy-driven interactions during nanofunctionalization, with hydrogen bonding contributing to a small percentage of the total binding enthalpy according to the proposed adsorption model.