• Important: PLEASE indicate any safety, exposure, handling, or disposal considerations prior to sample shipment in case RTS cannot properly accommodate.​

• ​Temperature Range: 0 to 200°C. 

• Sample Volume: Ideally >2mL per assay.  If sample is limited, depending on sample properties, assays may be performed with >150uL/assay (moderate viscosity) and >25uL/assay (high viscosity) transferrable sample using a small plate and small plate gap although accuracy and precision may decrease.  Having additional sample is often helpful if further method refinement and repeat analyses are necessary.

• Replicates: Multiple replicates (n>2) are recommended depending on desired precision.  At least triplicate assays are required to determine standard deviation and %RSD.

• Performance Standards: Bracketing performance standards are assayed before and after each assay set to confirm proper rheometer operation.  Water or certified silicone oil for rotational assays and PDMS for oscillatory assays are used.  Results are included in report.​

• Volatiles:  Please note if sample contains components that are potentially volatile, including water at assay temperatures.  Volatiles loss will likely affect results if not accommodated by using a solvent trap (shown below) to enrich/saturate the assay enclosure with the volatile(s).  Shipping the specific volatiles with samples would be helpful.  Please note that while volatiles loss may not be eliminated, it can be appreciably reduced.

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• Particles: Depending on other assay parameters, solids (>200-300um) can bind rheometer plates leading to variability.  With client approval, larger solids can be removed.  Ideally, the largest particle in the assay aliquot should be less than 1/10th the assay gap (typically <1mm). 

• Oxidation:  If sample is prone to oxidative degradation, assays can be performed under low-flow nitrogen in the enclosed assay chamber.  Request if needed.

• Moisture: If sample is moisture sensitive, assays can be performed under low-flow dry air or nitrogen (both approx. 15%RH) in the enclosed assay chamber.  Request if needed.

• Pre-shear: Unless requested, samples will not be intentionally pre-sheared.  Pre-shearing can be helpful to rheologically normalize samples; however, depending on the material sensitivity to shear thinning and subsequent rheological post-shear thinning and re-building (or lack of), some rheological properties may be erased.  It is recommended to consider pre-shearing if deemed necessary based on observed rheological properties of sample.  A thixotropy assay can provide insight into rheological rebuilding or lack thereof. 

• Low Viscosity: Low viscosity samples typically generate variable results at low shear rates. See Viscosity section for example.  Also see "Experimental Considerations" starting slide 28 in "Rheology Principles and Applications" for more details.

• Slippage:  Slippage at the plate-sample interface leads to experimental error and variability.  Unless specified otherwise, semi-solids will typically be assayed with a 25mm roughened parallel upper plate and roughened lower plate to reduce potential for slippage.  Low viscosity samples will be assayed with a smooth 40mm plate or 60mm/1deg cone.  If a smooth surface plate or cone is necessary, the absence of slippage can be screened by obtaining similar results using different loading gaps.  See Yield Stress section for more details.  

• High Shear Rate: Assays performed at high shear rates may require using a parallel plate with narrow sample gap (50-200um) to better retain sample within plates.  Cones have defined gaps that may be too wide.  In addition, the plot below shows low viscosity samples increasing viscosity due to flow turbulence >10,000sec-1 that then tend to dislodge from plates at higher shear rate (approx 50,000sec-1).  In this example, a narrower gap (<100um) may reduce potential for sample displacement and extend upper shear rate assay range.​​