Comparison of rheological behaviors with fumed silica-based shear thickening fluids

Abstract

Shear thickening fluids (STFs) of differing compositions were fabricated and characterised in order to observe the effect of varying chemical and material properties on the resultant rheological behavior. Steady shear tests showed that for a given carrier fluid and particle size exists an optimum weight fraction which exhibits optimal shear thickening performance. Testing also showed that increasing particle size resulted in increased shear thickening performance and its onset whilst altering the carrier fluid chemistry has a significant effect on the thickening performance. An explanation is provided connecting the effect of varying particle size, carrier fluid chemistry and weight fraction to the resultant rheological behavior of the STFs. Two STFs were chosen for further testing due to their improved but contrasting rheological behaviors. Both STFs displayed a relationship between steady and dynamic shear conditions via the Modified Cox-Merz rule at high strain amplitudes (γ0 ≥ 500%). Understanding the effects of particle and liquid polymer chemistry on the shear thickening effect will assist in 'tailoring' STFs for certain potential or existing applications. AbstractShear thickening fluids (STFs) of differing compositions were fabricated and characterised in order to observe the effect of varying chemical and material properties on the resultant rheological behavior. Steady shear tests showed that for a given carrier fluid and particle size exists an optimum weight fraction which exhibits optimal shear thickening performance. Testing also showed that increasing particle size resulted in increased shear thickening performance and its onset whilst altering the carrier fluid chemistry has a significant effect on the thickening performance. An explanation is provided connecting the effect of varying particle size, carrier fluid chemistry and weight fraction to the resultant rheological behavior of the STFs. Two STFs were chosen for further testing due to their improved but contrasting rheological behaviors.Both STFs displayed a relationship between steady and dynamic shear conditions via the Modified Coz-Merz rule at high strain amplitudes ( 0 ≥ 500%). Understanding the effects of particle and liquid polymer chemistry on the shear thickening effect will assist in 'tailoring' STFs for certain potential or existing applications.

Rheological and Technological Aspects in Designing the Properties of Shear Thickening Fluids

“…Silica is a primary choice as a solid phase for STF production [ 16 , 33 , 34 ], but other raw materials such as corn starch [ 35 ], calcium carbonate [ 36 ], titanium dioxide [ 37 ], polymethyl methacrylate [ 38 ], polystyrene [ 39 ], or ethyl polystyrene acrylate [ 40 ] are also used for this purpose. The continuous phase of an STF is usually ethylene glycol [ 41 , 42 ], poly(ethylene glycol) [ 32 , 43 , 44 ], propylene glycol [ 41 ], or poly(propylene glycol) [ 7 , 45 , 46 , 47 ]. There are also reports on the application of glycerin [ 48 ], ethanol [ 37 ], and even water [ 49 ].…”

Rheological modeling of multi-phase shear thickening fluid using an intelligent methodology

“…A recent approach, namely contact rheology model, supports the hydro-clustering theory in such a way that hydrodynamic interaction is responsible for the shear thickening onset at lower shear rates; however, at higher shear rates, the contribution of particle contacts within the hydro-clusters is much higher than the hydrodynamic interaction to the shear thickening mechanism [4,5]. STF rheology has been investigated by many researchers on the one hand [6][7][8][9][10][11]; STF has been adapted to different kinds of engineering applications on the other [12][13][14][15][16][17]. Since STF has been efficiently utilized in vibration damping systems [18][19][20], polishing processes [21,22] and protective structures [23,24], STF rheology should be understood in detail to adjust the systems as requested.…”

The influence of carbon nanotube addition on the properties of shear thickening fluid

“…The STFs consist of suspensions of solid phases in a carrier liquid. Polyethylene or polypropylene glycols and nanoparticles of fumed silica are mostly used for the fabrication of STFs [7,8]. STFs can also contain some additional modifications.…”