Nanoparticle Assembly at Fluid Interfaces:  Structure and Dynamics

• Published in: Langmuir Vol. 21; no. 1; pp. 191 - 194
• Main Authors: Lin, Yao, Böker, Alexander, Skaff, Habib, Cookson, David, Dinsmore, A. D, Emrick, Todd, Russell, Thomas P
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 04.01.2005
• Subjects: Chemistry; Colloidal state and disperse state; Exact sciences and technology; General and physical chemistry; Physical and chemical studies. Granulometry. Electrokinetic phenomena; Surface physical chemistry; Self assembly; Monolayer; Atomic force microscopy; Fluctuations; X ray microscopy; Nanoparticle; Transition metal Compounds; Device; In situ; Fluid; Fluorescence; Electron microscopy; Design; Particle; Chemical reduction; Interface structure; Liquid; Adsorption; Energy; Dynamics; X ray scattering; Cadmium Selenides; Interface; Photobleaching
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/la048000q

The self-assembly of nanoparticles at fluid interfaces, driven by the reduction in interfacial energy, was investigated. With spherical, tri-n-octyl-phosphine-oxide covered cadium selenide (CdSe) nanoparticles (1−8 nm), thermal fluctuations compete with the interfacial segregation giving rise to a size-dependent self-assembly of the particles. The structure of the nanoparticle assembly was studied using electron microscopy, atomic force microscopy, and X-ray scattering in situ, which indicate that the particles form a densely packed monolayer. The energetics of the adsorption of nanoparticles onto the interface was revealed by time-dependent fluorescence studies on a mixture of two different sized nanoparticles at the interface. The dynamics of the nanoparticles at the fluid interface, probed using fluorescence photobleaching methods, suggests a liquid-like behavior. The results have implications in the design of hierarchical self-assemblies of nanoparticles for the one-step fabrication of devices on multiple length scales.