Friction Reduction Properties of Micelles Related to Their Structure

1 Friction Reduction Properties of Micelles Related to Their Structure  

It can be noticed that, in all cases, friction is reduced as soon as the ttibologic tests start and remains stable up to the end of the tests. The friction coefficients obtained for various oc-tanoate salts are summarized in Table 4.3. The friction coefficient decreases from octanoic acid (0.17) down to 0.11 for overbased calcium octanoate and 0.1 for OCABS. Assuming a dependency of the friction coefficient on the adsorbed film thickness already established by many authors in the case of organic acids, esters, hydrocarbons, etc. [41, 42], this variation of the friction coefficient is attributed to the increasing size of the adsorbed film 

Maximum pressure (Hertz) Mean pressure Sliding speed Temperature 

1 % Sr octanoate in dodecane 1 % overbased Ca octanoate in dodecane 1 % oveibased Ca alkyl aryl sulfonate in dodecane Pure dodecane 

In the case of organic acids or Sr, Ba and Zn soaps, the adsorbed film is a monomolecular film with a thickness close to the molecular length. In the case of overbased calcium compounds the adsorbed film consists of nano-sized particles with a thickness of the order of the particle diameter including the organic shell. 

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