Shear Piezoresistive Response of a Graphite/Silicone Suspension

2006 ◽  
Author(s):  
John Edmiston ◽  
Yuri M. Shkel
Keyword(s):  
Shear Flow ◽  
Experimental Approach ◽  
Second Harmonic ◽  
Viscoelastic Liquid ◽  
Rheological Characteristics ◽  
Piezoresistive Effect ◽  
Material Parameters ◽  
Oscillatory Shear Flow ◽  
Measurement Results ◽  
Liquid Suspensions

A shear piezoresistive effect has been observed for micrographite particles suspended in uncured silicone elastomer. A phenomenological formulation of piezoresistivity is presented and an experimental approach is discussed within this paper. The experimental objective is to extract two material parameters, fully describing the piezoresistance effect in deformed isotropic materials. A rheometer in the cone-and-plate configuration provides well-defined oscillatory shear flow of the suspension; it also measures rheological characteristics of the suspension. The piezoresistive response is probed using interdigitated electrodes, which are attached to the rheometer plate. The electrodes are arranged in parallel-to-flow and perpendicular-to-flow orientations. The signal acquired from two such orthogonal electrode pairs can be combined in a way to exclude any contribution of volumetric deformations to the piezoresistance signal. The experimental results indicate a second harmonic relationship between the mechanical oscillation and the resistive response. These two-probe measurement results represent the first observations of a non-volumetric deformation contribution to the piezoresistivity of viscoelastic liquid suspensions.

The first normal stress difference of non-Brownian hard-sphere suspensions in the oscillatory shear flow near the liquid and crystal coexistence region

Soft Matter ◽  
2020 ◽  
Vol 16 (43) ◽  
pp. 9864-9875
Author(s):  
Young Ki Lee ◽  
Kyu Hyun ◽  
Kyung Hyun Ahn
Keyword(s):  
Shear Flow ◽  
Normal Stress ◽  
Hard Sphere ◽  
Normal Stress Difference ◽  
Oscillatory Shear ◽  
Stress Difference ◽  
Large Amplitude Oscillatory Shear ◽  
First Normal Stress Difference ◽  
Oscillatory Shear Flow ◽  
Sphere Suspensions

The first normal stress difference (N1) as well as shear stress of non-Brownian hard-sphere suspensions in small to large amplitude oscillatory shear flow is investigated.

Stable, highly concentrated suspensions for electronic and ceramic materials applications

1991 ◽  
Vol 6 (5) ◽  
pp. 1082-1093 ◽  
Author(s):  
I. Sushumna ◽  
R.K. Gupta ◽  
E. Ruckenstein
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Ceramic Materials ◽  
Rheological Characteristics ◽  
Concentrated Suspensions ◽  
Thermal Paste ◽  
Electrical Conductivities ◽  
Liquid Suspensions ◽  
Very High ◽  
Highly Loaded

Highly concentrated solid-in-liquid suspensions find applications in a number of areas such as electronics, ceramics, paints, coatings, etc. Highly loaded, stable suspensions which exhibit desirable rheological characteristics (moderate viscosity, shear thinning behavior, thixotropy, and a small yield stress, for example), and which have high thermal or electrical conductivities are frequently sought after. We describe here some techniques which can be used to obtain such highly concentrated suspensions. These involve employing mixed size grades of particles and effective dispersants. For thermal paste applications, for example, compliant pastes of up to 78 vol. % solids with thermal conductivity values as high as 6 W/mK (hence, a few times greater than the values reported previously by others), low electrical conductivity, and moderate viscosity have been prepared by mixing different particle size grades of materials such as Al2O3, SiC, AlN, Al, and diamond. Effective dispersants, both commercial as well as those synthesized in our laboratory as novel variations of previously known molecular architectures, have been used to facilitate the achievement of these very high loading and stable suspensions.

Dynamic simulations of individual macromolecules in oscillatory shear flow

2009 ◽  
Vol 53 (2) ◽  
pp. 275-291 ◽  
Author(s):  
Dennis G. Thomas ◽  
Ryan J. DePuit ◽  
Bamin Khomami
Keyword(s):  
Shear Flow ◽  
Oscillatory Shear ◽  
Dynamic Simulations ◽  
Oscillatory Shear Flow

Order in polymeric liquids under oscillatory shear flow

2019 ◽  
Vol 31 (3) ◽  
pp. 033103 ◽  
Author(s):  
Mona A. Kanso ◽  
L. Jbara ◽  
A. J. Giacomin ◽  
C. Saengow ◽  
P. H. Gilbert
Keyword(s):  
Shear Flow ◽  
Oscillatory Shear ◽  
Polymeric Liquids ◽  
Oscillatory Shear Flow
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