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Microgels as viscosity modifiers influence lubrication performance of continuum
Efren Andablo-Reyes1, Demetra Yerani, Ming Fu
1Food Colloids and Bioprocessing Group, School of Food Science and Nutrition, University of Leeds, UK. A.Sarkar@leeds.ac.uk.
Soft Matter
|October 12, 2019
Summary
Whey protein microgels modify fluid viscosity, impacting friction and lubrication. Their performance depends on microgel rigidity and the surrounding fluid
Area of Science:
- Colloidal science
- Materials science
- Tribology
Background:
- Biocompatible microgels are known lubricants.
- The influence of the surrounding fluid (continuum) on microgel mechanical performance is understudied.
- Understanding this interaction is crucial for optimizing microgel-based lubrication systems.
Purpose of the Study:
- To investigate the mechanical performance of colloidal whey protein microgels.
- To determine how different continuum properties (Newtonian vs. non-Newtonian fluids) affect microgel lubrication.
- To explore the role of microgel rigidity in tribological behavior.
Main Methods:
- Rheology was used to measure the mechanical properties of microgel dispersions.
- Soft tribology techniques were employed to assess lubrication performance.
- Microgels of varying rigidity were dispersed in Newtonian (buffer, corn syrup) and non-Newtonian (xanthan gum) fluids.
Main Results:
- Microgels acted as thickeners in low-viscosity fluids, reducing friction, with harder microgels showing greater friction reduction.
- In high-viscosity fluids, microgels acted as thinning agents, increasing friction.
- Lubrication behavior varied: Newtonian fluids showed effective viscosity related to the second Newtonian plateau, while complex fluids exhibited more nuanced responses.
Conclusions:
- Microgels function as effective viscosity modifiers, directly influencing tribological performance.
- The interplay between microgel properties (rigidity) and continuum rheology dictates lubrication outcomes.
- This study highlights the importance of the continuum's properties in microgel-based lubrication systems.
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