Helene Yockell-Lelievre

arXiv2014

Single step synthesis and organization of gold colloids assisted by copolymer templates

We report here an original single-step process for synthesis and self-organization of gold colloids by simply incorporating gold salts into a solution prepared with Polystyrene (PS) - Polymethylmethacrylate (PMMA) copolymer, thiolated PS and Propylene Glycol Methyl Ether Acetate (PGMEA) as solvent. The spin-coating and annealing of this solution allows then the formation of PS domains. Depending on the polymer concentration of the as-prepared solution, there can be either one or several gold nanoparticles (NPs) per PS domains. For high concentration of gold nanoparticles in PS domains, the coupling between plasmonic nanoparticles leads to the observation of second peak in the optical extinction spectrum. Such collective effect could be relevant for the development of optical strain sensors in the next future.

cond-mat.mtrl-sci↗

arXiv2003

Optical Tests of Nanoengineered Liquid Mirrors

We describe a new technology for the fabrication of inexpensive high-quality mirrors. We begin by chemically producing a large number of metallic nanoparticles coated with organic ligands. The particles are then spread on a liquid substrate where they self-assemble to give optical quality reflective surfaces. Since liquid surfaces can be modified with a variety of means (e.g. rotation, electromagnetic fields), this opens the possibility of making a new class of versatile and inexpensive optical elements that can have complex shapes which can be modified within short time scales. Interferometric measurements show optical quality surfaces. We have obtained reflectivity curves that show 80% peak reflectivities.We are confident that we can improve the reflectivity curves, for theoretical models predict higher values. We expect that nanoengineered liquid mirrors should be useful for scientific and engineering applications. The technology is interesting for large optics, such as large rotating parabolic mirrors, because of its low cost. Furthermore, because the surfaces of ferrofluids can be shaped with magnetic fields, one can generate complex, time varying surfaces difficult to make with conventional techniques.

physics.optics↗