Nanocomposites and nanomaterials
Thermally-driven self-assembly of liquid-crystalline metal nanoparticles into helical systems
Bagiński M.1, Tupikowska M.1, Lewandowski W.
1 University of Warsaw, Faculty of Chemistry, Pasteura 1 Street, 02-093 Warsaw, Poland. 
E-mail: mbaginski@chem.uw.edu.pl

    The main aim of our research is to develop a universal method that allows to obtain materials in which we are able to arrange various types of nanoparticles into helical systems. Specifically, we aim at helical, hierarchical structures that exhibit reversible reconfigurability.
      In our current studies we prepared materials made of spherical gold nanoparticles (Figure 1A) and gold nanorods (Figure 1B) covered with proper promesogenic surface ligand. These nanoparticles were mixed with a liquid-crystalline, organic template, that was structurally similar to surface ligand. Due to  the interactions between the organic template material and nanoparticles, on cooling from the melt, the organic material forms helical nanofibers decorated with nanoparticles (nanoparticles form double helical structure). The obtained superstructures were thoroughly studied using TEM, SEM, XRD and AFM methods. 
A                           B                                                                  

Figure 1. TEM images of helical systems made of (A) 4 nm diameter spherical nanoparticles; (B) gold nanorods.
  
The research is conducted under Reinforce project carried out within the First Team programme of the Foundation for Polish Science co-financed by the European Union under the European Regional Development Fund.