ADSORPTION OF SURFACTANTS ON LOW-CHARGED LAYER SILICATES .2. ADSORPTION OF NONIONIC SURFACTANTS

Nonionic surfactants were adsorbed on low-charged layer silicates in the interlayers. After drying, the surfactants were arranged in densely packed double layers. However, in suspension considerably higher basal spacings are measured by x-ray diffraction which indicate that large quantities of non-ionic surfactants are adsorbed. With the aid of calorimetry, enthalpies of displacement were recorded which suggest strong interactions of the non-ionic surfactants with smectites. In analogy to tests on hydrophilic SiO2, the adsorption of smectites is found to depend on the degree of ethoxylation of the non-ionic surfactant. The adsorption declines with increasing EO content.