Abstract
The review summarizes the literature data and the authors’ own research results on the application of liquid crystals in tribology. It has been shown that both thermotropic (calamitic, discotic, cholesteric) and lyotropic (surfactants, chromonics) mesogens as tribological additives are able to optimize the properties of lubricating compositions when introduced even at low concentrations to oils and greases. A wide possibility of varying the chemical structure of mesogens and studying the relationship between their structure and tribological properties can be used for the desired (programmed) change of the quality of tribotechnical processes. The synergism of the combined use of mesogenic esters of cholesterol and carbon nanostructures as additives in improving tribological properties has been established. The use of synthetic lubricants in biological systems still requires further research as the experimental results obtained on models of joint prostheses in vitro conditions are significantly worse than the results obtained in vivo. Considering the annual loss of billions of US dollars worldwide due to the low efficiency of friction processes in the industry and the resulting wear, liquid crystals and the systems based on them can be the most effective way to optimize these processes. The present review will be useful for researchers and industrialists.
Highlights
Long before the introduction of the term “tribology”, which for the first time was used in 1966 [1,2]and combines a set of scientific and technological ideas about interacting surfaces when they move relative to each other, a number of phenomena displaying in this area were discovered
The study of liquid crystals at the empirical level occurred at the end of the 19th and the electronics: the creation of information display screens, including computers, light emitting diodes, beginning of the 20th century, but later, a significant impetus to its further development gave the solar panels, etc
Based on the experimental data on the thermodynamic and the rheological characteristics of the cholesteric liquid crystal (CLC)–Sh over the temperature range of the existence of SmA and N* phases and isotropic liquid, as well as a comparison of the results with those previously published for the CLC–multi-walled carbon nanotubes (MWCNT) systems [38], we revealed the general tendency of the carbon nanoparticle concentration to have an insufficient effect on the temperature range of the N* phase existence and on the expansion of the SmA phase temperature range
Summary
Long before the introduction of the term “tribology”, which for the first time was used in 1966 [1,2]. The graphic characteristics of the friction regime were obtained by Professor Stribeck (1861–1950) of the Royal Prussian Institute of Control (Berlin) [3]. Practically all technical universities have groups dealing with tribology problems. The theory and practice of implementing tribological processes have attracted increasing attention as objects of interdisciplinary research that have a serious impact on the economies of developed countries. Obtaining the most efficient lubricants is a technological problem, it is an important economic one, since half of the consumed energy is spent on friction [5]. A critical analysis of the literature data and the authors’ own results regarding the use of thermotropic and lyotropic mesogens in technical and biological systems as ‘smart’ materials that allow the development of new lubricants with programmable properties is presented
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
