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Fuel economy has become the dominant criterion in the design of new automobiles. The globally enacted targets for fleet average emissions pose true challenges to automobile manufacturers. Increasing fuel economy requires enhancements both in hardware as well as in lubricant performance. As a key component of the lubricant, poly(alkyl methacrylate) PAMA viscosity index improvers have been identified as crucial design element due to their multiple modes of action. In their original application, they serve the well-known mechanism of polymer coil expansion at high temperatures and collapse at low temperatures. They help to flatten the viscosity/temperature relationship of the lubricant and allow for reduced low temperature viscosities and reduced internal friction, which directly translates into fuel economy. In addition to this bulk application, interfacial tribological phenomena contribute significantly to efficiency and fuel economy.

The efficiency of lubricated machine elements such as transmissions, crankcase engines, and hydraulic pumps depends strongly on the friction properties of the lubricant employed. For the design of modern, highly efficient lubricants it is thus essential to understand the influence of the components of the lubricating fluid in terms of film formation and consequent friction. The influence of Polyalkylmethacrylate (PMA) Viscosity Index Improvers on those important parameters has been studied by means of optical interferometry and friction testing. Low friction coefficients and positive contributions to the boundary film thickness of the lubricant were obtained when composition and architecture of the polymeric VII were appropriately designed.