Abstract
In a typical passenger car approximately 33 % of fuel energy is wasted trying to overcome friction. Efficient and optimized lubricants are key to reducing friction within engines, reducing fuel consumption, wear, and the release of associated CO2 emissions into the atmosphere.Reverse micelles in oily media are known lubricating agents which raises a question about the effects of micellar structure (size and shape – spherical, cylindrical, or wormlike) on friction reduction. Non-spherical micelles (e.g., wormlike) are often highly viscous fluids, acting akin to covalent polymeric systems but with the added relaxation mechanism of micellar scission.
This thesis focuses on methods utilized to drive the formation of non-spherical reverse micelles such as surfactant counterion exchange, varying water content, and the addition of hydrotropes. Techniques such as viscometry and small-angle neutron scattering have been used to aid the tracking of micellar transitions and to help discern whether tuneability of micellar sizes and lengths is possible through a combination of these methods. Two investigations were undertaken to test tuneability: increasing the x value from 0 to 0.3 (where x = [Hydrotrope] / [Surfactant]) of a hydrotrope; and maintaining x = 0.1 but varying the hydrotrope chain length from C2 to C8. Phase behaviour studies were conducted to find stable microemulsion regions. Collaborations were established to investigate the micellar behaviour after shearing, at the metal/liquid interface, and the impact micellar shape may have on traction coefficients. This work has offered the first
initial step in investigating the effect of micellar structure on friction reduction, which can be built upon for future work and future development of super-efficient lubricants.
| Date of Award | 9 May 2023 |
|---|---|
| Original language | English |
| Awarding Institution |
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| Sponsors | Infineum UK Ltd |
| Supervisor | Julian Eastoe (Supervisor) & Paul Bartlett (Supervisor) |
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