Engineered silica nanoparticles as additives in lubricant oils

Area of Science:

• Materials Science
• Nanotechnology
• Tribology

Background:

• Silica nanoparticles (SiO2 NPs) often aggregate in base oils, limiting their use as lubricant additives.
• Surface modification is crucial for enhancing nanoparticle dispersibility and performance in lubricant applications.

Purpose of the Study:

• To engineer SiO2 NPs with improved dispersibility and tribological properties for lubricant applications.
• To investigate the effect of surface functionalization on nanoparticle stability and performance in base oils.

Main Methods:

• Sol-gel synthesis of SiO2 NPs followed by surface modification with long-chain alkyl functionalities (lauric acid, decanoyl chloride).
• Characterization using SEM, TEM, FTIR, DTA, NMR, and DLS.
• Dispersion stability analysis using static multiple light scattering in base oils.
• Tribological performance evaluation of nanoparticle dispersions.

Main Results:

• Surface functionalization with hydrophobic chains successfully prevented SiO2 NP aggregation and improved dispersibility in base oils.
• The stability of SiO2 NP suspensions was dependent on the functional layer's nature and degree of functionalization.
• Functionalized SiO2 NPs significantly reduced friction coefficient and wear in tribological tests.
• The dendritic structure of the nanoparticle surface layer was key to improved tribological characteristics.

Conclusions:

• Engineered SiO2 NPs with tailored surface properties are effective lubricant additives.
• These nanoparticles offer a promising, environmentally friendly solution for reducing energy loss due to friction.
• The study highlights the potential of functionalized SiO2 NPs in hydraulic circuits and other demanding applications.