Perspective of Tribological Mechanisms for α-Alkene Molecules with Different Chain Lengths from Interface Behavior

Area of Science:

• Tribology
• Materials Science
• Surface Chemistry

Background:

• Lubricant performance is critical for reducing friction and wear in mechanical systems.
• Understanding the fundamental properties of lubricants, such as chain length, is essential for developing advanced materials.
• Existing research often investigates multiple lubricant variables, making it difficult to isolate the effect of chain length.

Purpose of the Study:

• To investigate the sole influence of alpha-alkene chain length on tribological properties.
• To explore the relationship between chain length, surface energy, and adsorption energy.
• To elucidate the underlying mechanisms responsible for improved lubrication performance.

Main Methods:

• Selection of three alpha-alkene lubricants with varying chain lengths (1-decene, 1-tetradecene, 1-octadecene) as model compounds.
• Utilized the Owens-Wendt-Rabel-Kaelble (OWRK) method and density functional theory (DFT) to calculate surface and adsorption energies.
• Performed tribological tests to measure friction coefficients and wear volumes, followed by characterization to analyze wear mechanisms and tribochemical reactions.

Main Results:

• Average friction coefficients decreased sequentially with increasing chain length: 1-decene (0.125), 1-tetradecene (0.099), and 1-octadecene (0.075).
• Wear volume significantly reduced with longer chains: 53.2% decrease for 1-tetradecene and 64.0% for 1-octadecene compared to 1-decene.
• Both surface energy and adsorption energy increased with chain length, positively impacting tribofilm formation and lubricant adsorption.

Conclusions:

• Increasing alpha-alkene chain length enhances both surface and adsorption energies, leading to superior tribological performance.
• Long-chain alpha-alkenes (1-octadecene, 1-tetradecene) exhibit better lubrication properties than short-chain counterparts (1-decene).
• This study provides fundamental insights into the intrinsic relationship between lubricant chain length and tribological behavior, aiding in the design of high-performance lubricants.