Novel applications of nanoparticle dispersions in lubrication and bio-lubrication

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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.