Dynamic photo-switchable soft nanomaterials made of platinum group metals nanoparticles and small plasmonic nanoparticles modified with promesogenic ligands

Wójcik M.M.1, Tomczyk E.1, Lewandowski W.1
1 Faculty of Chemistry, University of Warsaw, Pasteura Str. 1, 02-093 Warsaw, Poland 
E-mail:mwojcik@chem.uw.edu.pl
    Condensed aggregates of periodically organized nanostructures are among the most important research topics for the development of nanoengineering and dynamic control of physicochemical properties.[1] We shown that spherical nanoparticles  can  organize  into  many  diverse  structures  when  substituted  by  mesogenic  ligands. [2] In special cases the distance between nanoparticles in  the superlatice could be controlled by light-driven conformational changes in organic grafting layer (azobenzene), that gave possibility to dynamically control the plasmonic  properties of hybrid materials.4,5,6  
In this presentation, a novel approach for synthesis and characterization of liquid crystalline plasmonic nanoparticles will be shown. The new type of nanoparticles has been obtained as a result of anti-galvanic reduction (AGR) and post-synthetic modification of nanoparticles surface with promesogenic ligands. 
By using this approach, small noble metals nanoparticles can be obtained, the ordering of which is easily controlled by organic ligands. Despite very small diameter AGR treated nanoparticles exhibiting strong plasmonic properties that are dependent on the ordering of the nanoparticles in the liquid crystalline phase.
Conducted temperature measurements and UV-VIS measurements showed that changes in the ordering of nanoparticles result in changes in the optical properties of the entire system. 

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