TY - JOUR
T1 - Correlation Between the Adsorption and the Nanotribological Performance of Fatty Acid-Based Organic Friction Modifiers on Stainless Steel
AU - Zachariah, Zita
AU - Nalam, Prathima C.
AU - Ravindra, Amogha
AU - Raju, Archana
AU - Mohanlal, Anupama
AU - Wang, Kaiyu
AU - Castillo, R. Veronica
AU - Espinosa-Marzal, Rosa M.
N1 - Publisher Copyright:
© 2019, Springer Science+Business Media, LLC, part of Springer Nature.
PY - 2020/3/1
Y1 - 2020/3/1
N2 - Surface adsorption of amphiphilic molecules is a vital mechanism of boundary lubrication on stainless steel surfaces. The self-assembly of four fatty acid-based organic friction modifiers in two alkane solvents and their adsorption onto stainless steel surfaces was investigated using Dynamic Light Scattering and Quartz Crystal Balance with Dissipation, respectively. These properties were related to the friction force between a sharp tip and the steel surface measured using Lateral Force Microscopy. The molecular structures of the organic friction modifiers were chosen in order to study the effects of unsaturation and number of alkyl chains as well as the composition of the polar head groups on their assembly in solution, adsorption, and nanotribological behavior. Sorbitan monooleate and dioleate adsorb as monolayers with their alkyl chains either in the upright or tilted configuration, depending on their concentration. If large supramolecular structures were present in the solvent, i.e., for sorbitan monolaurate and glycerol monooleate, micelle adsorption and rearrangement on the surface and multilayer formation took place, respectively. A correlation between the adsorption rate constant and the coefficient of friction of the organic friction modifiers was revealed in these studies, with the coefficient of friction decreasing with an increase in the adsorption rate. Graphic Abstract: [Figure not available: see fulltext.].
AB - Surface adsorption of amphiphilic molecules is a vital mechanism of boundary lubrication on stainless steel surfaces. The self-assembly of four fatty acid-based organic friction modifiers in two alkane solvents and their adsorption onto stainless steel surfaces was investigated using Dynamic Light Scattering and Quartz Crystal Balance with Dissipation, respectively. These properties were related to the friction force between a sharp tip and the steel surface measured using Lateral Force Microscopy. The molecular structures of the organic friction modifiers were chosen in order to study the effects of unsaturation and number of alkyl chains as well as the composition of the polar head groups on their assembly in solution, adsorption, and nanotribological behavior. Sorbitan monooleate and dioleate adsorb as monolayers with their alkyl chains either in the upright or tilted configuration, depending on their concentration. If large supramolecular structures were present in the solvent, i.e., for sorbitan monolaurate and glycerol monooleate, micelle adsorption and rearrangement on the surface and multilayer formation took place, respectively. A correlation between the adsorption rate constant and the coefficient of friction of the organic friction modifiers was revealed in these studies, with the coefficient of friction decreasing with an increase in the adsorption rate. Graphic Abstract: [Figure not available: see fulltext.].
KW - Atomic force microscopy
KW - Boundary lubrication
KW - Carboxylic acid derivative
KW - Organic friction modifier
KW - Quartz crystal microbalance
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U2 - 10.1007/s11249-019-1250-z
DO - 10.1007/s11249-019-1250-z
M3 - Article
AN - SCOPUS:85075933292
SN - 1023-8883
VL - 68
JO - Tribology Letters
JF - Tribology Letters
IS - 1
M1 - 11
ER -