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Hyperbranched Poly(octadecyl Acrylate)s as Lubricant Additive Studied by Resonance Shear Measurement
Yutaka Takahashi1, Yuzhong He2, Yuhan Jiang2
1New Industry Creation Hatchery Center (NICHe), Tohoku University, Sendai, Miyagi 980-8577, Japan.
Langmuir : the ACS Journal of Surfaces and Colloids
|November 24, 2025
Summary
Hyperbranched polymers (HBPs) offer superior lubrication compared to linear polymers. These novel lubricant additives reduce friction and wear in both hydrodynamic and boundary regimes.
Area of Science:
- Materials Science
- Tribology
- Polymer Chemistry
Background:
- Lubricant additives are crucial for enhancing performance, but linear polymers increase viscosity.
- Low viscosity lubricants excel in hydrodynamic but falter in boundary lubrication, increasing friction and wear.
Purpose of the Study:
- To investigate hyperbranched polymers (HBPs) as novel lubricant additives.
- To compare the performance of HBPs against linear polymers in a poly(α-olefin) (PAO) base oil.
Main Methods:
- Synthesis of HBPs with controlled structures via organotellurium-mediated radical polymerization.
- Evaluation of lubricant performance using viscosity measurements, resonance shear measurements, and macroscopic friction tests.
Main Results:
- HBP solutions maintained low fluid resistance, unlike linear polymers which increased viscosity.
- HBPs demonstrated superior nanoscopic lubrication efficiency: HBPs > linear polymers > PAO.
- Significant reduction in the coefficient of friction was observed in the boundary lubrication regime with HBPs.
Conclusions:
- Hyperbranched polymers (HBPs) provide effective lubrication across both hydrodynamic and boundary regimes.
- HBPs represent a promising new class of lubricant additives for reducing friction and wear.
