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Liquid-crystalline nanoparticles: a new approach to energy efficient and tunable nanomaterials

Event Details

Event Dates: 

Thursday, August 28, 2014 - 12:00pm

Seminar Location: 

  • Duane Physics Room D142

Speaker Name(s): 

Michal Wojcik

Speaker Affiliation(s): 

University of Warsaw
Seminar Type/Subject

Scientific Seminar Type: 

  • Condensed Matter Seminar

Event Details & Abstract: 

Condensed aggregates of periodically organized nanostructures are among the most important research topics for the development of nanoengineering and dynamic control of physicochemical properties. The range of application could be broader if they form well defined, large-scale structures. We show that spherical nanoparticles  can  organize  into  many  diverse  structures  when  substituted  by  mesogenic  ligands,  due  to  the self-segregation  of  chemically  non-compatible  units. Nematic,  smectic  columnar  and  3D superstructures were observed in which metal cores  and organic parts self-segregate in space. The type of structure can be controlled by composition of grafting layer and temperature as well as by the metal core size and density of grafting layer. In special cases the distance between nanoparticles in  the superlatice could be controlled by light-driven conformational changes in organic grafting layer (azobenzene derivatives), that gave possibility to control the plasmonic  properties of hybrid materials. We show strategies used to synthesize liquid-crystalline nanoparticles as well as discuss parameters influencing structural and thermal characteristic of aggregates. We also demonstrated that the liquid-crystalline approach offers access to dynamic self-assembly and metamaterials with anisotropic plasmonic properties, which makes this strategy unique among others.