Коллеги,
9 марта в 17.00 в Ц-02а состоится семинар выпускника ФНМ Евгения Смирнова. Это будет сообщение по материалам диссертационной работы, выполненной под руководством профессора Жиро (H. Girault) и защищенной в École polytechnique fédérale de Lausanne. Очень красивые системы!
Assemblies of gold nanoparticles at liquid-liquid interfaces: from liquid optics to electrocatalysis
Abstract: The interface between two immiscible liquids, i.e. oil and water, is an extremely attractive scaffold to self-assemble nanoparticles (NP) in arranged films. The liquid-liquid interfaces (LLIs) are defect-free and pristine by the nature, they are transparent and self-healing as well as mechanically flexible. The present work is devoted to self-assembly of gold NPs into nanofilms at various LLIs and further investigation of their optical, mechanical and electrochemical properties. It consists of two large parts: (i) self-assembly of gold nanoparticles into Metal Liquid-Like Droplets (MeLLDs) and (ii) electrocatalytic capability of nanoparticles placed at the interface.
In the first part we showed that the irreversible adsorption of AuNPs at LLIs was achieved by charging nanoparticles with a lipophilic electron donor, tetrathiafulvalene (TTF). The present process was facile and required only vigorous shaking of organic phase with TTF and aqueous phase with AuNPs. Detailed study of optical properties demonstrated that MeLLDs could be used as liquid mirrors and filters with tuned optical response by varying NPs size, concentration and the solvent’s nature.
Further, we investigated ion and electron transfer (ET) properties of nanoparticle assemblies. A new method was developed to prepare nanofilm in four-electrode electrochemical cell. It consisted in precise microinjection of pre-concentrated solution of AuNPs in methanol directly at the ITIES. Primary achievement of this technique was prevention pollution of aqueous and organic phases. The nanofilm occupied roughly 30% of available surface area and did not interfere with the ion transfer across the ITIES. However, these films showed a capability to be charge by electron donors in organic phase with subsequent formation of the corresponding ions and discharge in the adjunct phase with significantly improved kinetics of the interfacial ET reaction.That property of nanofilms was used to reduce oxygen by decamethylferrocene (DMFc) in neutral condition with formation of hydrogen peroxide.