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Rheology Testing Services Performs Viscosity & Viscoelasticity Assays & More!​​​​​​

Deliverables
Scientific Rigor & Experience
Collaboration & Responsiveness
Flexibility with Rapid Turn-around
Detailed Report
No Bureaucratic Hurdles
Cost Effective Support for Small & Large Projects

 

Rheology Applications​
Research & Development
Process Optimization
Batch Consistency & Stability

Sensory Properties
Manufacturing (QbB, Quality by Design)
In-process Control
​Prove/Disprove Equivalence for Regulatory & IP (Q3)

Kinexus Pro rheometer to assay viscosity, viscoelasticity, amplitude sweep, frequency sweep, temperature sweep, shear thinning, yield stress, flow curves, tribology and surface tension.
Rheological assay of lotion viscosity
Comparison of shear rate ramp flow curves for viscosity determination of non-Newtonian mayonnaise and Newtonian honey.
Amplitude sweep as % strain to compare elastic modulus and LVER of hydrogels
Using shear stress ramp and shear rate ramp to measure viscosity and yield stress.
Frequency sweep of silly putty viscoelasticity change with frequency as elastic modulus, viscous modulus and phase angle.

"I wished we reached out to you much earlier in the R&D process to better rheologically understand our product and the impact of manufacturing conditions, especially before locking down specifications."  Comments like this have been mentioned by RTS clients more than a few times.  Performing either a single assay to address a specific technical need or an array of assays to generate a comprehensive rheological profile, is often a very small investment with a potentially large return.

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RTS provides a broad range of rheological assay options with flexibility, no bureaucracy and rapid turnaround for clients ranging from academics, start-ups to international conglomerates.  In contrast to many large "all-in-one" Contract Research Organizations (CRO) and Contract Development and Manufacturing Organizations (CDMO),  RTS is focused on rheology.  RTS clients particularly appreciate the very responsive and personalized interactions along with real-time flexibility and technical experience that RTS consistently provides, especially for the "Houston we have a problem" situations (see "Testimonials" below).

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Not sure what assays and parameters would be most appropriate to address the question you seek to answer? 

No problem - RTS will provide guidance.

OFTEN REQUESTED ASSAYS
Additional assays listed under "Assays" tab (page top)

Learn more about Rheology Testing Services performs analyses to understand the impact of viscosity on materials during processes and applications.

Viscosity with Shear Rate Ramp

Viscosity (resistance to flow) is one component of a detailed rheological profile to support product development.

 

Viscosity can be quantified with several methodologies. A frequently requested assay is the rotational shear rate ramp applied across a wide range of conditions. For example: Honey being a Newtonian fluid does not appreciably shear thin with increasing shear rate; whereas, mayonnaise (non-Newtonian) does.

 

Typically, these assays are helpful to generate shear thinning or flow curves that efficiently model processes and applications. ​

Learn more about Rheology Testing Services performs analyses to understand the impact of yield stress on materials during processes and applications.

Yield Stress with Shear Stress Ramp

Yield stress is often determined by a shear stress ramp assay to quantify the rheological "breakpoint" that leads to flow.

 

For example:  While on a flat surface, a spoonful of yogurt spreads (flows) over a relatively short time has a much lower yield stress & yield viscosity than peanut butter, which takes much longer to spread.

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Yield stress determinations are helpful to model pumpability, spreading, delivery, sedimentation potential (Stokes' Law) and feel.

Learn more about Rheology Testing Services performs analyses to understand the impact of amplitude sweep on materials during processes and applications.

LVER with Amplitude Sweep

An amplitude sweep is an oscillatory assay during which amplitude (energy input as either strain or stress) increases over time and frequency is held constant.

 

During this assay, the sample is increasingly deformed during back & forth oscillation to determine its rheological breakpoint (LVER; Linear Viscoelastic Region) which correlates with rheological stability.  As described in the next panel, knowing the LVER is important to determine the experimental strain or stress input for frequency-modulated assays.

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An analogy for amplitude sweep is when molded gelatin is wiggled beyond its LVER, it falls apart. 

Learn more about Rheology Testing Services performs analyses to understand the impact of frequency sweep on materials during processes and applications.

Viscoelasticity with
Frequency Sweep

A frequency sweep is another oscillatory assay during which amplitude (either strain or stress) is held constant and frequency changes over time. This assay is often used to quantify viscoelastic properties for materials that are not amenable to rotational assays.  The typical  measurables for frequency sweep assay is stiffness (G*; complex modulus), solid nature (G'; elastic or storage  modulus), liquid nature (G"; viscous or loss modulus), degree of fluidity (phase angle), complex viscosity, and tan delta (G"/G').  

 

To properly perform this assay, it is important to use a strain or stress input within its LVER determined from amplitude sweep.  This ensures the sample's rheological integrity is maintained during the assay and hence validity of the results.

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Silly Putty is an excellent example of changing viscoelastic properties with frequency. When near at rest (low frequency), it slowly spreads like a liquid (G">G'). However, when rolled into a ball and dropped on a table (high frequency), it bounces like a solid (G'>G"). Check out "Learn More" below to see actual plot.

TESTIMONIALS

“We contacted Mark to outsource our rheology characterization tests. Not only did he provide the required results in a timely manner, he went above and beyond to provide detailed reports with the right context to help us understand the results, especially when the data showed unexpected results. He is always available to discuss the results in more detail as needed. His expertise in non-Newtonian fluids helped us successfully complete our project.”  
 
- Siddharth Talapatra, PhD  Group Lead, Research   Heat Transfer Research, Inc.
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