Lubrication by Lamellar Liquid Crystals - An in-situ investigation of thin films with Brewster Angle microscopy technology

Tribology/lubrication are enabling technologies which can mitigate the 23% (119 EJ) of the world energy consumption originating from tribological contact. Potential savings estimated at 1-1.4% of the gross national product, 8.7% of total global energy consumption and a reduction in CO2 emissions by up to 3140 MtCO2 are possible through three groundbreaking approaches: the large-scale computational modelling of tribological systems, experimental methods with in-situ capabilities and novel materials including lubricants and additives. The development of advanced lubricants and additives is particularly promising as they are expected to exceed half of these estimated potential savings in each of the five areas: engine and drivetrain, wind turbines reliability and efficiency, metalworking, marine and rail industries. Our proposal is aligned to address two of those approaches, namely exploring new lubricants and their in-situ characterization. The material of choice for advanced lubricants is a type of liquid crystals, namely lamellar liquid crystals. Their low shear strength between layers, solid-like elasticity, high load carrying capacity and increased biodegradability have significant potential for high fuel efficiency, longer lifespans of machinery, reduced maintenance, increased environmental friendliness - all important drivers for a global shift to renewable and energy efficient operation. Understanding how LC properties could be exploited for lubrication has been limited mainly because of the lack of suitable methods to characterise them in tribological contacts. To address this challenge, we propose a new technique based on microscopy exploiting Brewster angle reflection to monitor and visualise in real time, lubricants in tribological contacts. The method, which we called Brewster Angle microscopy Plus (BAM Plus) will be applied for the first time to tribological systems. It will allow us not only to visualise, but also develop qualitative and quantitative information on molecular-thin layers in static and dynamic contacts. Understanding the mechanism behind the low friction properties of lamellar liquid crystals, their interaction with surfaces and alignment under pressure and/or shear will facilitate the development of a new class of efficient, green lubricants based on them. The application of BAM Plus to other types of organic/biomaterials will demonstrate its versatility and potential for breakthrough in lubricant development research.