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

摩擦学/润滑是一种使能技术，可以减少23% （119 EJ）由摩擦学接触引起的世界能源消耗。通过以下三种突破性的方法，估计可以节省国民生产总值的1-1.4%，占全球能源消耗总量的8.7%，并减少高达31.4亿吨二氧化碳的二氧化碳排放：摩擦学系统的大规模计算建模，具有原位能力的实验方法以及包括润滑剂和添加剂在内的新型材料。先进润滑油和添加剂的开发尤其有前景，因为它们有望在发动机和传动系统、风力涡轮机的可靠性和效率、金属加工、船舶和铁路行业这五个领域中节省一半以上的潜在成本。我们的建议与其中两种方法相一致，即探索新的润滑剂及其原位表征。高级润滑剂所选择的材料是一种液晶，即层状液晶。其层间剪切强度低，弹性类似固体，承载能力高，生物降解性强，具有提高燃油效率，延长机械寿命，减少维护，提高环境友好性的巨大潜力-所有这些都是全球向可再生能源和节能运营转变的重要驱动因素。了解如何利用LC特性进行润滑主要是因为缺乏合适的方法来表征它们在摩擦学接触中的特性。为了解决这一挑战，我们提出了一种基于显微镜的新技术，利用布鲁斯特角反射来实时监测和可视化摩擦学接触中的润滑剂。我们称之为Brewster角度显微镜Plus （BAM Plus）的方法将首次应用于摩擦学系统。它将使我们不仅可以可视化，而且还可以在静态和动态接触中开发分子薄层的定性和定量信息。了解层状液晶低摩擦特性背后的机制，它们与表面的相互作用以及在压力和/或剪切下的排列将有助于开发基于它们的新型高效绿色润滑剂。BAM Plus在其他有机/生物材料上的应用将展示其多功能性和润滑油开发研究的突破潜力。

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.