Tip-induced orientational order of surfactant micelles on gold

Citation:

Schniepp, H. C. ; Saville, D. A. ; Aksay, I. A. Tip-induced orientational order of surfactant micelles on gold. Langmuir 2008, 24, 626-631.

Date Published:

Feb

Type of Article:

Article

ISBN Number:

0743-7463

Accession Number:

WOS:000252777700007

Abstract:

Using liquid-cell atomic force microscopy, we investigate aqueous solutions of alkyltrimethylammonium halide surfactants at the Au(III) surface. The long, micellar surfactant surface aggregates cover the gold surface completely and exhibit two types of orientational order for chloride and bromide counterions, respectively. We observe lateral forces perpendicular to the scanning direction, which we explain by anisotropic friction between the probe and the oriented micelles. Conversely, we show that these friction forces can be employed to modify the spatial conformation of the micellar adlayer. Where previous methods have failed to provide control over the orientation down to the level of individual micelles, we use this technique to achieve a very high degree of order over more than 100 micelle diameters.