Novel applications of nanoparticle dispersions in lubrication and bio-lubrication

克服摩擦消耗了大量能源，产品和部件的磨损及其更换造成了重大的经济损失。新一代润滑剂的开发具有重要的技术和经济意义，因为据估计，目前使用的世界能源中有五分之一需要用来克服这样或那样的摩擦。因此，任何摩擦和磨损的减少都可以节省大量的能源。在不影响润滑性能的情况下，使用环保润滑剂作为油基润滑剂的替代品也是理想的。通过将纳米添加剂分散到水中，水基纳米润滑剂已成为一种很有前途的环保润滑剂。水对环境友好，价格便宜，容易获得，不易燃，具有高导热性。随着纳米润滑技术的发展和人们对功能纳米材料认识的不断深入，纳米颗粒作为添加剂显示出独特的物理化学性质，在润滑领域有着广阔的应用前景。水基纳米润滑剂的使用不仅可以防止摩擦和磨损，还可以提高产品的整体质量，在金属成形等工程应用中显示出巨大的潜力。这一研究计划的重点将放在含有纳米添加剂的水基润滑剂的研究上，它们的相图显示出液晶状态。液晶是一种各向异性材料，兼具传统液晶和固体晶体的特性。研究表明，LCS能形成具有良好承载能力的有序边界层，并能降低滑动表面的摩擦系数、磨损率和接触温度。外加电场和磁场会影响液晶分子的取向。利用电场或磁场来控制润滑性能是设计智能润滑剂的第一步，具有许多工业和生物医学应用。这一研究计划将带来先进的、可预测的工具，以提高对纳米溶解机理的理解，并从长远来看，提出新的、经济上可行的、更高效的、高性能的环保智能纳米润滑剂。本研究项目针对纳米颗粒及其自组装的水基润滑剂的基本问题，采用建模、计算和实验相结合的方法来研究其润滑性能和导致这种性能的机理。

A considerable amount of energy is consumed to overcome friction, and major economic losses are due to wear of products and components and their replacement. The development of a new generation of lubricants is of paramount technological and economic relevance since it is estimated that one-fifth of the world's energy resources in present use are needed to overcome friction in one form or another. Hence, any reduction in friction and wear can result in considerable energy savings. It is also desirable to use eco-friendly lubricants as alternatives to the oil-based ones without compromising on the lubrication performance. Water-based nanolubricants have been emerging as promising eco-friendly lubricants by dispersing nano-additives into water. Water is environmentally friendly, inexpensive, readily available, and non-flammable and has high thermal conductivity. With the development of nanolubricating technology and the deepening understanding of functional nanomaterials, nanoparticles used as additives show unique physical and chemical properties and have a broad application prospect in lubrication. The use of water-based nanolubricants not only provides protection against friction and wear, but also improves overall the quality of the product, demonstrating a great potential in engineering applications, such as metal forming. The focus of this research program will be on the study of water-based lubricants with nano-additives, exhibiting liquid crystalline state in their phase diagram. Liquid crystals (LCs) are anisotropic materials with properties of both conventional liquid and solid crystals. The ability of LCs to form ordered boundary layers with good load-carrying capacity, and to lower the friction coefficients, wear rates and contact temperatures of sliding surfaces has been demonstrated. External electric and magnetic fields affect the orientation of liquid crystal molecules. The usage of electric or magnetic field to control lubrication properties is the first step towards designing smart lubricants, with many industrial and biomedical applications. This research program will lead to advanced, predictive tools to improve the nanolubrication mechanism understanding, and long term to propose new, economically viable, more efficient high performance environmentally friendly smart nanolubricants. This research program addresses fundamental questions underlying the water-based lubricants added by nanoparticles and their self-assembly, combining modelling, computation and experimentation to study the lubrication performance and the mechanism leading to that performance.