A study of lubrication by liquid crystals

Kupchinov, B. I.; Rodnenkov, V. G.; Ermakov, S. F.; Parkalov, V.P.

doi:10.1016/0301-679x(91)90059-i

Cited by 14 publications

(8 citation statements)

References 1 publication

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“…Mori et al [10], it has been reported that COFs of sliding contacts, which were lubricated with MFs, reached ultralow values (l \ 0.005). It was published that these COFs were realized under various loads and mixtures with standard lubrication oils [6,[12][13][14][15][16][17][18][19][20][21][22]. Ultralow friction was also detected in a real engineering application [23].…”

Section: Introductionmentioning

confidence: 96%

Relationship Between Ultralow Friction of Mesogenic-Like Fluids and Their Lateral Chain Length

Amann

Kailer

2010

Tribol Lett

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Mesogenic fluids (MFs) may have a great potential for technical applications to increase the energy efficiency and to prevent wear. Aim of the present work was to study a homologous series of mesogenic-like fluids to evaluate the influence of the chemical structure on the tribological behavior. Rheological measurements were additionally performed to correlate the tribological properties with the viscosity and flow behavior. Raman spectroscopy and differential scanning calorimetry measurements were used to characterize the MFs. Furthermore, the surface topography of the wear scar was studied by profilometry. The results were summarized and hence an approach was made to describe the several mechanisms which may lead to the observed tribological results. This work shows that a better understanding of the tribological behavior of these MFs is essential to develop new lubricants.

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Section: Introductionmentioning

confidence: 96%

Relationship Between Ultralow Friction of Mesogenic-Like Fluids and Their Lateral Chain Length

Amann

Kailer

2010

Tribol Lett

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“…First attempts to correlate the chemical structure of liquid crystals (LC)-compounds with the achieved coefficient of friction were made by Mori et al [12]. In addition, there have been some few studies concerning the antifriction properties of LCs as lubricant additives [9,10,[14][15][16][17]. In summary, these publications demonstrate the possibility to improve the tribological properties by using mesomorphic phases as pure lubricants or as additives to base oils.…”

Section: Introductionmentioning

confidence: 98%

“…Kupchinov et al [7] provided the verification that the low friction of joints in living organisms results from liquid crystalline substances in the synovial fluid. Pure liquid crystalline fluids were already tested in real engineering applications [8] and demonstrated unusual lubricating properties in many cases [9][10][11][12][13], but very little is known about their antiwear and friction reducing potential [10,14]. First attempts to correlate the chemical structure of liquid crystals (LC)-compounds with the achieved coefficient of friction were made by Mori et al [12].…”

Section: Introductionmentioning

confidence: 99%

Ultralow Friction of Mesogenic Fluid Mixtures in Tribological Reciprocating Systems

Amann

Kailer

2009

Tribol Lett

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Tribological systems that are lubricated with mesogenic fluids may exhibit ultralow friction coefficients. This effect, which has not yet been well examined, has been reproducibly observed in a reciprocating friction system after a certain running-in period in different mixtures with two reference lubricants. Aim of the present work was to study the tribological behavior of different mesogenic fluids as pure lubricants and in mixtures with standard lubrication oils. Surface analysis was performed to correlate the tribological characteristics with surface features. A basic approach is described to explain the several effects, which lead to the observed results. A better understanding of the tribological behavior is essential for the development of efficient production methods and for the qualification of mesogenic lubricants for possible future applications.

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“…Behavior where the viscosity in sliding direction is reduced while the viscosity perpendicular to the sliding direction, i.e., in the direction of the load, is rather high, is frequently called thin-film lubrication. LCs have already been intensively investigated as pure lubricants [31] and as additives in mineral oils [32,33] and water [34,35]. A new field of research is currently opening up in the field of ionic liquid crystals (ILCs) [29], also in combination with water [36,37].…”

Section: Introductionmentioning

confidence: 99%

Macroscopic Friction Studies of Alkylglucopyranosides as Additives for Water-Based Lubricants

et al. 2020

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Water-based lubricants might become an interesting alternative to conventional oil-based lubricants and help to reduce wear as well as improve the energy efficiency of transport processes. Since pure water is generally a rather poor lubricant due to its low viscosity and corrosiveness, it must be tribologically optimized with suitable additives. Here, we study the friction behavior of alkyl glucopyranosides (AGPs) with varying lengths of the alkyl chain. Sliding experiments show that a significant reduction in the coefficient of friction compared to that of pure water is observed. The extent of friction reduction depends strongly on the concentration and on the shearing conditions. It is assumed that the low coefficients of friction are due to the ability of AGPs to form liquid crystalline phases with an ordered structure in the friction gap. Furthermore, the interaction of the AGPs with the surface forms a wear protection layer (boundary lubrication). The friction properties of the water-based system are compared to those of a conventional, mineral oil-based lubricant.

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A study of lubrication by liquid crystals

Cited by 14 publications

References 1 publication

Relationship Between Ultralow Friction of Mesogenic-Like Fluids and Their Lateral Chain Length

Relationship Between Ultralow Friction of Mesogenic-Like Fluids and Their Lateral Chain Length

Ultralow Friction of Mesogenic Fluid Mixtures in Tribological Reciprocating Systems

Macroscopic Friction Studies of Alkylglucopyranosides as Additives for Water-Based Lubricants

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