Modeling and Characterization of Nanoparticle-Doped Colloidal Fibers under Solution Blow Spinning

Blowing nanoparticle-doped polymer colloidal suspension with high-speed airflow is a commonly used method for fabricating functional fibers. However, theoretical models capable of accurately describing the fiber formation process remain limited. This is primarily due to the tendency of polymer jets to undergo deformation and instability under strong airflow, which becomes more pronounced when nanoparticles are introduced. To address this issue, a dynamic rheological model was developed in this study to predict the fiber formation behavior of nanoparticle-doped polymer colloidal suspension under high-speed airflow. The model incorporates multiphysical mechanisms (airflow shear force, surface tension, and viscoelasticity) and considers the indirect influence of nanoparticles on the flow evolution. The numerical simulations accurately predicted the evolution of the fiber diameter (<i>R</i>² = 0.87-0.98) and lateral oscillation amplitude (<i>R</i>² = 0.70-0.88) under various processing conditions, showing good agreement with the experimental measurements. In addition, the real-time observation of jet dynamics was performed using dual-plane high-speed imaging. The experimental results indicated that an appropriate number of nanoparticles could enhance the viscoelasticity of the solution, suppress initial disturbances, and improve fiber stability. However, for the higher nanoparticle concentration, the shear thinning efficiency decreased, resulting in an increase in the fiber diameter and a lateral oscillation amplitude. In contrast, increasing the gas pressure strengthened the shear forces and promoted fiber thinning; however, higher pressure gradually transformed the airflow field into a nonstationary state, amplified the lateral oscillations, and eventually led to a nonlinear jet breakup. These findings provide new insights into the stability and process control of nanoparticle-doped fibers.