RHEOMETER vs VISCOMETER
A rheometer provides much more insight into your product properties
A viscometer is well suited as a QC tool - simple to use and relatively inexpensive to purchase, maintain and operate. A viscometer typically provides a viscosity result under a single set of defined conditions that may provide insight into a relatively small rheological properties window.
In contrast, a rheometer is a versatile R&D and problem solving instrument to perform an array of rotational, oscillational, and vertical geometry movements with relatively a small volume (typically100uL to 1mL/assay) to probe a broad range of rheological responses to applied forces and conditions such as stress, strain, shear, temperature, amplitude, frequency, tribology (friction), vertical compression/pull-away and surface tension. These properties include, but are not limited to stringiness, stickiness, adhesion, cohesion, pumpability, suspension stability, texture, thixotropy, structural characterization, spreadability, and physical and thermal stability.
The above tabs describe in more detail just some of the primary rheology measurements and their applications that RTS offers to help you better understand your product properties. RTS provides rapid turn-around, is very flexible and often perform investigative one-off analyses to meet your particular rheological needs.
Figure 1 highlights an important potential oversight when using a viscometer to determine viscosity at a single shear rate instead of a rheometer measuring across many shear rates. This classic example using a rheometer shows mayonnaise (black curve) being more viscous than honey (gold curve) at lower shear rates (<14/sec), both have same viscosity at 14/sec, and then become less viscous than honey at >14/sec due to shear thinning. The response to increasing shear rate shows the shear thinning mayonnaise to be "non-Newtonian". In contrast, honey maintaining a constant viscosity is "Newtonian". The extent and rate of a shear thinned sample to rheologically rebuild can be quantified with a "Thixotropy".