<p>The tribological properties of two polymethyl methacrylate (PMMA) copolymers were studied, both of which were specially synthesized by the living-anion polymerization method using highly concentrated methyl methacrylate, lauryl methacrylate and stearyl methacrylate as monomers. Chemical structure of PMMA was identified as block and random copolymers by ¹³C nuclear magnetic resonance, gel permeation chromatography and Fourier transfer infrared analysis. The presence of adsorbed films on iron oxide was confirmed by atomic force microscopy with tapping mode. In addition, the block copolymer was greater film thickness than the random copolymer from the topographic image. From the EHL test, the block copolymer solution formed a thicker oil film, and showed a lower traction coefficient than the random copolymer solution at low speeds. On the other hand, both the polymer solutions showed almost the same coefficient of friction in the ultra-low speed test. In other words, the block copolymer has better traction properties in the partial EHL region due to its better oil film-forming ability than the random copolymer. Furthermore, the partial EHL analysis revealed that the oil film behavior was influenced by the polymer enriched film at the inlet region in the case of the random copolymer and dominated by the viscoelastic properties of the adsorption film in the case of the block copolymer.</p>