Molecular self-assembly relies on various non-covalent interactions between well-defined molecular level building blocks. However, at higher length scale utilization of such supramolecular interactions in the self-assembly of colloidal level building blocks such as nanoparticles (organic/inorganic) is challenging, due to aggregation tendencies, polydispersity and difficulties in controlling the directionalities of the building blocks. In nature, biological particles, such as virus capsid self-assemblies are inspirational examples for sub-unit based hierarchical structure formation. They represent one of the fascinating examples for genetic economy, efficiency and error-free structure formation. In this presentation, I will show how to control the synthesis of nanoparticles at atomic precision and their self-assembly to obtain hierarchical superstructures (Figure 1).[1,2] The special emphasis will be on free-standing 2D nanosheets with one nanoparticle thick layer (2.5 nm) and their bending to hollow spherical capsids with monolayer thick shell. Further, the importance of monodisperse building blocks for designing chiral plasmonic polarizers will be discussed.
1. Nonappa, T. Lahtinen, J. S. Haataja, H. Häkkinen, O. Ikkala. Angew. Chem. Intl. Ed. 2016, 55, 16035-16038.
2. Nonappa, J. S. Haatja, J. V. I. Timonen, S. Malola, P. Engelhardt, N. Houbenov, M. Lahtinen, H. Häkkinen, O. Ikkala. Angew. Chem. Int. Ed. 2017, 56, 6473-6477.
3. Nonappa, O. Ikkala. Adv. Funct. Mater. 2017 (manuscript accepted).
4. V. Lisjström, A. Ora, J. Hassinen, H. Rekola, Nonappa, M. Heilala, V. Hynninen, J. Joensu, R.H. A. Ras, P. Törma, O. Ikkala, M. A. Kostiainen. Nat. Commun. 2017, 8, Article number : 671