Elucidating the effects of dispersion methods on agglomerated nano silica particles in aqueous environment

Abstract

A zero-dimensional Nano silica (NS) particle possess a wide range of application in multi-variant fields due to its size, amorphous nature and silica content in spite of its hydrophilic and hydrophobic behaviour. These nano particles are synthesized and commercially supplied in the size range of 1–100 nm with high Specific Surface Area (SSA). Due to agglomeration, these NS particles are sized between 1 and 100 μm which in turn reduces its SSA and thereby limiting its efficient utilisation. As a pragmatic solution, the current study involves in defining the suitable dispersion method for NS particles in aqueous environment. The effects of both mechanical and physical surface modification of nano particles using Superplasticizer (SP) since the incorporation of NS particles that aim at cementitious system are investigated. NS particles acts as nucleation seeds in cement hydration which directly relay on its particle size. The mechanical modification methods such as Ultrasonication and high shear mixer are employed to reduce the agglomerates size. Whereas the effect of steric (electrostatic mechanism) and Vander Waals attraction between the deagglomerated particles are studied. The stability and the size histogram of deagglomerated nano particles are thoroughly assessed with Dynamic Light Scattering (DLS) technique. From the findings, it is interpreted that the combination of mechanical and surface modification effectively reduces the size of agglomerates as well as the intensity of surface attractive forces between the particles with respect to its dosage in aqueous medium.