The micromorphology and large amplitude oscillatory shear behaviors of hydrocarbon gel fuels filled with fumed silica and aluminium sub-microparticles

The gel network structure filled with attractive nanoparticles (NPs) significantly affects the viscoelasticity of the nanocomposites , which is poorly understood and troubles industrial processes. In this work, the nanoparticle gel matrices were prepared with hydrophilic fumed silica (FS), and filled with aluminium sub-microparticles (Al SMPs) loading in the range of 10%− 50%. The effects of particle content and composition on the large amplitude oscillatory shear (LAOS) behaviors are investigated by stress decomposition methods. Meanwhile, the higher harmonics and the Chebyshev harmonics coefficients were obtained. We found that the gels exhibit consistent progressive stiffening with particles filling, companying with plastic transformation and weak strain overshoot (WSO). With aluminum increasing, nonlinear viscoelastic responses gradually weaken in LAOS, severely decreasing the linear viscoelastic (LVE) region, and were validated by strain stiffening index S , T and high-order harmonics. In confocal microscopy (CFM) images, the aluminum particles were fluorescently labeled and found to be adhered together with FS clusters. This article could provide a perspective on understanding the flow mechanism of particulate network structure by combining morphological details and LAOS behaviors.