The Crystal Structure and Tribology of a Novel Organic Crystalline Powder: the Mechanism of Lubricity

Abstract

A novel lubricant material, calcium N-lauroyl taurate (C11H23CONH(CH2)2SO3·0.5Ca, CaLT), has been synthesized and characterized. The powder of CaLT is a plate-shaped crystal with a lamellar structure. CaLT shows superior lubricity as a result of its unique internal and aggregate structure. When the CaLT powder is applied to an artificial skin, the frictional coefficient is favorably lower than that of other solid lubricants of similar type. The frictional coefficient of CaLT decreases rapidly at initial passage and becomes constant when CaLT is repeatedly rubbed onto an artificial skin. The high lubricity may result from disintegration of the powder aggregates, cleavage of the lamellar layers and deformation of the powder particles. This novel lubricant material, CaLT, will be a powerful ingredient of some cosmetic and/or personal-care products in the near future.

Lubricant and Bactericidal Properties of Calcium Salts of Fatty Acids: Effect of Degree of Unsaturation

“…The adhesion energy between solid particles decreases with increasing hydrophobicity of the surfaces. Previously, we reported that a surfactant divalent metal salt, Ca salt of N-lauroyl taurate, forms a thin layer due to cleavage and disintegration; however, the lamellar structure still remained after deformation 5,6 . Conversely, C18:2 fatty acid Ca salt is not suitable for the absorption of frictional energy by cleavage due to its amorphous structure.…”

“…The difference between the lubrications of these three Ca salts of fatty acids is caused by their crystal structures. In the cases of C18:0 and C18:1 fatty acid Ca salts, the lubricity is due to three factors 5,6,13 . The first and second factors are cleavage of the lamellar layers and disintegration of the powder aggregates.…”

Palmitoleic Acid Calcium Salt: A Lubricant and Bactericidal Powder from Natural Lipids

“…The adhesion energy between solid particles decreases with increasing hydrophobicity of the surfaces. Previously, we reported that one of surfactant divalent metal salts, N-lauroyl taurate Ca salt, forms a thin layer due to the cleavage and disintegration, although the lamellar structure still remained after the deformation 15,16 . The thin layer was hydrophobic: a water droplet formed a spherical lens on the layer.…”

“…The lubricity of surfactant divalent metal salts, including the C16:1 fatty acid Ca salt, is determined by three factors. The first and second factors are cleavage of the lamellar layers and disintegration of the powder aggregates 15,16 . These disruptions in the structural systems can absorb the friction force between solid surfaces.…”

Phase Transitions of Branched Fatty‐Acid Calcium Salt/Water Systems

“…Divalent metal salts of surfactants, known as "scum," are powdery materials used in many applications such as ingredients of lubricants and cosmetics, thermal stabilizers, water repellent agents, and fuel additives (Gregory and Spink, 1947;Morin and Briens, 2013;Nonomura et al, 2002aNonomura et al, , 2002bWendt and Wagner, 1954). Particularly, cosmetics and foods contain stearic acid calcium (Ca) salt, which is also used as a lubricant for powder formulations and anticaking agents.…”