A New Class of Photoresponsive Surfactants

In this thesis, a new class of nonionic, photoresponsive surfactants consisting of a polar di(ethylene oxide) head group attached to an alkyl spacer of between two and eight methylene groups, coupled through an ether linkage to an azobenzene moiety, were synthesized and developed. Structural changes associated with the interconversion of the azobenzene group between its cis and trans forms as mediated by the wavelength of an irradiating light source, cause changes in the surface tension, critical micellization concentrations (CMC), and self-assembly behavior. Differences in saturated surface tensions (at concentrations above their CMCs) were as high as 14.4 mN/m under radiation of different wavelengths. This large and reversible change in saturated surface tensions in response of different illumination conditions made these new surfactants have potential applications in the pumping and control of flow in microfluidic devices, and in the microchemical analysis of complex fluids, flow cytometry, rapid DNA screening