Thermal rheology and microstructure of shear thickening suspensions of silica nanoparticles dispersed in the ionic liquid [C₄mim][BF₄]

Molten Li Salt Solvate-Silica Nanoparticle Composite Electrolytes with Tailored Rheological Properties

“…These observations concur with our previous findings regarding the anion dependent sol/gel states for imidazolium-based AIL-silica composites; i.e., the silica suspensions in [ 17 The macroscopic difference in the MLS-silica composites is attributable to the morphological difference in the aggregation/ dissociation state of the silica nanoparticles. In a previous study, the hydrogen bonds between the ions and the silica surface were found to play an important role in determining the colloidal interactions and consequently, the stability of nanoparticles in a dense ionic medium, such as ILs; 24 however, there exist complicated competitions between the cation-anion and nanoparticle-ion interactions. Molecular dynamic simulations of the ILs confined between amorphous silica slabs suggested that the surface silanol groups of silica are more engaged in hydrogen bonding with the anions for 25 The extensive hydrogen bonding ability of [BF 4 ]-based ILs with silica was considered to be responsible for the formation of a robust solvation layer of the ILs around the silica surface, which gave rise to the effective repulsive force to confer the colloidal stability in highionic-strength media where the electrostatic force does not contribute to interparticle repulsion.…”

“…Molecular dynamic simulations of the ILs confined between amorphous silica slabs suggested that the surface silanol groups of silica are more engaged in hydrogen bonding with the anions for 25 The extensive hydrogen bonding ability of [BF 4 ]-based ILs with silica was considered to be responsible for the formation of a robust solvation layer of the ILs around the silica surface, which gave rise to the effective repulsive force to confer the colloidal stability in highionic-strength media where the electrostatic force does not contribute to interparticle repulsion. 20,24,26 Figure 1 shows the effect of variations in the shear rate on the shear viscosity of the MLS-silica composites at V silica = 0.08. The dispersions containing [TFSA]-based MLSs exhibited a similar change in the viscosity in response to the application of shear, i.e., both exhibited a significantly high shear viscosity (>2 © 10 3 Pa s) at a low shear rate of 1 s ¹1 , and the viscosity decreased with the increasing shear rate.…”

Effect of Particle Specific Surface Area on the Rheology of Non-Brownian Silica Suspensions

“…The suspension at is used for the PS226 particles, as this is the highest volume fraction achieved to provide a homogeneous sample based on visual inspection. The suspensions exhibit viscous dominated behaviour, with the values being higher than the , at all experimental conditions and particle characteristics, indicating the hindrance of direct particle contacts due to the presence of the solvation layer [ 23 ] in the whole range of angular frequencies investigated. Increasing the particle specific surface area leads to increasing both and values as compared with the glass sphere suspension.…”

“…Gao et al were able to measure the thickness of this solvation layer for fumed silicas suspended in an aqueous solvent using the small angle neutron scattering (SANS) technique. The measured thickness was found to span a few nanometers with a maximum value of 3 nm at room temperature [ 23 ].…”

Rheological study of new dispersions of carbon nanotubes in the ionic liquid 1-ethyl-3-methylimidazolium dicyanamide

“…ILs have attracted a growing interest in the fields of materials science and engineering, tribology and lubrication technologies [19][20][21][22][23]. The development of large numbers of new ILs with many different technological applications and their ability to disperse the different carbon structures and nanoparticles are among their main advantages [12,[24][25][26][27]. Fukushima et al have firstly reported the preparation of CNT-IL gels, in a large scale by mechanical grinding, with applications in several fields such as sensors, actuators and electrochemistry [24,28,29].…”