Spinverse Expert Dr. Markku Heino has co-authored two scientific papers regarding nanomaterials published just recently in the web. Both papers are based on his work at Nokia Research Center, NanoSciences lab. showing the results of the cooperation between NRC and Aalto University.
J. Raula, M. Makowska, E. Kauppinen, E. Seppälä, M. Heino, J. Tarus, N. Runeberg, A. Sillanpää, J. Lahtinen, H. Jiang, “Selective Covalent Functionalization of Carbon Nanobuds”, Chemistry of Materials Communication 22, 4347 (2010). http://pubs.acs.org/doi/abs/10.1021/cm100716g
The paper shows a new way to achieve functionalized carbon nanotubes (CNT), i.e. CNTs with desired molecules attached as side branches. This makes the otherwise inert (non-reactive) and bundled CNTs to disperse well in solvents (even water) and makes it possible to mix them well with polymers to achieve nanocomposites with useful properties. Using the carbon nanobuds (discovered earlier by Prof. Kauppinen’s group) instead of ordinary CNTs we can attach the side branches on the fullerene bud of tube backbone firmly, but without sacrifying the good properties of the nanotube. This important finding was first analyzed and explaimed by theoretical calculations showing clear selectivity of several molecules to react with the fullerene part instead of the CNT backbone, and then proven in practice by careful experimental work with selected amine compounds. The results are significant and the finding can make such functionalized CNTs really potential molecular lego blocksfor building new multifunctional nanomaterials with unprecedented properties.
E. Pohjalainen, M. Pohjakallio, C. Johans, K. Kontturi, J. Timonen, O. Ikkala, R.Ras, T. Viitala, M. Heino, and E. Seppälä, “Cobalt Nanoparticle Langmuir-Schaefer Films on Ethylene Glycol Subphase”, Langmuir, in press (2010), Publication Date (Web): August 5, 2010. http://pubs.acs.org/doi/abs/10.1021/la101630q
Magnetic thin films were prepared from cobalt nanoparticles using so called Langmuir-Schaefer technique. The work included synthesis of Co nanoparticles with controlled size (9 nm), stabilizing them with tridodecyl amine, preparation of the thin films by casting from ethylene glycol sub-phase, and characterization of the film formation process and prepared thin films e.g. by Brewster angle microscopy (BAM), transmission electron microscopy (TEM) and SQUID magnetometer. The film formation process is very sensitive, but by careful selection of the solvent, sub-phase and a secret additive, PS-b-PEO block-co-polymer we achieved homogeneous super-paramagnetic films of nanometer-scale thickness. The result shows that it is possible to make magnetically active thin films using stabilized Co nanoparticles with organic shell protecting them from oxidation.