The interactions between eight ionic liquids and a rolling hydroxylated silicon surface are modeled in this report using various semi-empirical methods. The eight modeled ionic liquids consist of two sets of four ionic liquids from separate tribology studies. The first set of four ionic liquids contain the l-butyl-3-methyl imidazolium cation (BMIM~+) and include BMIM~+-BF4_4~-, BMEVT-NO_3~-, BMIM~+-PF_6~- and BMEVT-CICV. The second set of ionic liquids contains the l-methyl-3-X imidazolium cation and a Cl- anion. The four imidazolium sidechains (X) include -C_3H_6OH, -C_2H_4CN, -C_3H_7 and -C_2H_4COOH. The individual ionic liquids form complexes with the hydroxylated silicon surface and the enthalpies of complex formation calculated using PM3, PM5 and PM6 semi-empirical methods. The PM3 and PM5 computed ionic liquid-surface complex enthalpies of complex formation (Δ_rH) correlate with the measured frictional coefficients of these ionic liquids. These results allow the investigator to possibly predict the success or failure of other ionic liquids once a baseline is established.
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