Karlsson Philip M, Palmqvist Anders E C, Holmberg Krister
Department of Chemical and Biological Engineering, Applied Surface Chemistry, Chalmers University of Technology, SE-412 96 Göteborg, Sweden.
Langmuir. 2008 Dec 2;24(23):13414-9. doi: 10.1021/la802198s.
The adsorption of two anionic surfactants, sodium dodecyl sulfate (SDS) and sodium dodecyl phosphate (SDP), at surfaces of aluminum and aluminum oxide has been studied by means of atomic absorption spectrometry (AAS), X-ray photoelectron spectroscopy (XPS), and quartz crystal microbalance with dissipation monitoring (QCM-D). It was shown that more SDP than SDS binds to the surface and that SDP prevents dissolution of aluminum in water whereas SDS does not. This was not obvious, since the adsorption isotherms of the two surfactants to aluminum pigment powder are quite similar, as shown in an earlier work. The decreased aluminum dissolution with SDP compared to SDS was explained by the formation of a more compact protective layer with less permeability on the aluminum surface with SDP than with SDS. This is explained by differences in complexing ability between the surfactants and the aluminum pigment surface. While SDP is expected to form an inner-sphere complex with aluminum, leading to a lower accessibility of aluminum sites to water, SDS is likely to form a weaker outer-sphere complex.
通过原子吸收光谱法（AAS）、X射线光电子能谱法（XPS）以及带耗散监测的石英晶体微天平（QCM-D），研究了两种阴离子表面活性剂十二烷基硫酸钠（SDS）和十二烷基磷酸钠（SDP）在铝和氧化铝表面的吸附情况。结果表明，与SDS相比，更多的SDP会结合到表面，并且SDP能防止铝在水中溶解，而SDS则不能。这并不明显，因为正如早期工作所示，这两种表面活性剂对铝颜料粉末的吸附等温线非常相似。与SDS相比，SDP使铝溶解减少，这是由于在铝表面形成了比SDS更致密、渗透性更低的保护层。这可以通过表面活性剂与铝颜料表面络合能力的差异来解释。预计SDP会与铝形成内球络合物，从而降低铝位点对水的可及性，而SDS可能形成较弱的外球络合物。
