Exploring the impact of CoFe2O4 additives morphology on the properties of a novel strain-rate sensitive composite material

Abstract

Various additives in smart materials are attracting wide attention owing to the improved adaptable functions, such as the ferromagnetic additive. However, the effect of additives’ morphology is not well investigated, causing inconsistent phenomena reported for the same additive. In this work, the spherical and rod-shaped CoFe2O4 nanoparticles were prepared by varying the reaction process of solvothermal, and introduced as dispersed phases into strain rate-sensitive materials to fabricate new strain-rate sensitive composite materials. The influence of magnetic particle morphology on its rheological performance was investigated. The results showed that the strain-rate sensitive composites with rod-shaped CoFe2O4 (RCFO) have a higher storage modulus and viscosity than the ones with spherical CoFe2O4 (SCFO) nanoparticles. The relationship between shear rate and viscosity indicates that all samples exhibited significant shear thinning effects in the range of shear rates studied, and the RCFO nanoparticles are useful for achieving a higher viscosity in comparison to the SCFO nanoparticles at the same shear rate. This work proves that the morphology of additives plays an important role in adjusting the property of smart materials and is expected to present some principles to choose the suitable morphology of additives for the design of new magneto-rheological materials.