Interfacial properties and aggregates of novel redox-active surfactant to synthesize silver nanoparticles at the air/water interface

An anionic and amphiphilic molecule, AQua (AQ-NH-(CH2)10COOH; where AQ is anthraquinone), which has two stimuli responsive functional-groups, can form self-assembled interfacial aggregates at the air-water interface and, their morphologies can be controlled by changing the subphase conditions such as the pH of the subphase. These interfacial morphologies may be altered from planar structures to wormlike aggregates which is a very rare observation in the literature. Moreover, the unique functional groups of AQua give possibility to reduce metal cations and allow the formation of organic/inorganic nanocomposite structures at the interface. In this context, formation of silver nanoparticles (AgNPs) via AQua-based self-assembled structures at the interface was studied using Langmuir techniques. The kinetics of the reduction process as well as the effect of various parameters were systematically examined. This study demonstrates that interfacial configuration of the AQua molecule at the interface as well as its orientation has a vital role in the morphology of either organic or inorganic self-assemblies formed. The morphology may be adjusted and designed interfacial structures may be obtained. The interfacial properties of AQua, a novel material, may be used in a wide variety of fields such as biotechnology, medicine, energy and pharmaceuticals.