Fatty acid monolayers, adsorbate surface concentrations

Organic adsorbates that are more hydrophobic exhibit different adsorption behavior, particularly at higher concentrations. Long-chain fatty acids adsorb to oxide surfaces in part through surface complexation, as shown by electron spin resonance spectroscopy (32). At higher concentrations at the surface, however, favorable interactions between sorbed molecules (hemimicelle formation) appear to dominate and result in greater than monolayer adsorption (40, 41). Because humic substances (like the fatty acids) are amphiphilic, both surface complexation and hydrophobic interactions may be involved in the adsorption of humic substances on oxide surfaces. 

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