Adsorption of Nonionic Surfactants onto Hydrophilic Surfaces

Adsorption of Nonionic Surfactants onto Hydrophilic Surfaces 

A characteristic of the early neutron reflectivity studies of nonionic surfactant adsorption was some variability in the pattern of adsorption. This was investigated in more detail and more systematically by McDermott et al. [55], who compared the adsorption of Ci2E6 onto a range of different substrates, amorphous silica, crystalline quartz, and the oxide layer on a silicon single crystal. The adsorbed surfactant was found to form a bilayer with an overall thickness 49 4 A, with a structure similar to that determined in the previous studies (see Fig. 4). 

Although the same model was applicable for each of the different substrates, the adsorbed amount or fractional coverage varied between 40 and 75%. There was an implication in the data that this correlated with the surface roughness of the substrates, but the evidence is not conclusive. Subsequently, Penfold et al. [25] have considered the consequences of the different surface treatments on the adsorption of nonionic surfactants at the hydrophilic silicon-solution interface. The delicate nature of the cooperativity of the adsorption results in variations in the adsorbed amount, which depend strongly upon 

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