Formation of Metallic Nanostructures in Organic Matrix by Vapour and Plasma Phase Deposition and its Modification by Swift Heavy Iron Irradiation
Final Report Abstract
The aim of this collaborative research project was to produce mainly polymer-based nanocomposite materials, which consist of metal nanoparticles dispersed in a polymer matrix and exhibit many novel functional properties, and to induce nanostructural modifications upon swift heavy ion irradiations. It was planned to use approaches that allow formation of nanocomposites of well defined compositions. Two solvent free central methods of vapor phase co-deposition and plasma phase co-depostion were investigated in parallel for simultaneous deposition of metal and polymer. These complimentary codeposition techniques were expected to lead to the development of nanocomposite materials with the desired and optimized compositions. Preparatory studies already carried out in this direction had demonstrated the feasibility of the above approaches. Investigations were intended to explore the ability to tailor the nanostructures by ion beam irradiation in order to bring new changes in the nanostructure and the resulting quantum size effects. A crucial part of the project was the preparation of different nanocomposites with well defined nanostructure. In particular, it was important to control the filling factor of the metallic nanoparticles and their size within a relatively narrow distribution. This was achieved with vapour phase deposition of the organic precursor and the metallic component via both evaporation as well as sputtering. At the beginning, nanocomposites prepared by co-sputtering of Ag and Teflon were investigated extensively. Due to the particle surface plasmon resonance of the Ag nanoparticles they exhibit interesting optical properties. This system was used to measure changes in the particle size and distribution upon SHI irradiation, and the effect on the optical properties was studied. Subsequently, multilayers involving Ag-Teflon and Au-Teflon nanocomposites were prepared to explore mixing effects due to irradiation. In the next step, magnetic materials were used. Here interesting magnetic properties were obtained prior to ion irradiation, but no magnetic properties were observed after irradiation. Although the focus in the present project was clearly on polymer based systems, we also studied composites based on TiO2 matrices filled with Ag and Au nanoparticles. These investigations were also motivated by the observation of carbonization of the polymer matrices along the ion tracks at high ion fluences which could be avoided in the TiO2 matrices. Here however, the very interesting observation on ion beam induced nucleation of single crystalline TiO phase was made. Moreover, irradiation proved to induce very large changes in the noble metal nanostructure, particularly at high filling factor, which gave rise to strong changes in the particle surface plasmon resonance spectra. In sharp contrast to the behavior of polymer based nanocomposites, pronounced surface segregation was seen in the TiO2 based systems which was studied inter alia by an advanced electron tomography technique. The Ag containing nanocomposites also showed strong antibacterial properties due to very effective release of silver ions from the nanoparticles. Interestingly, ion irradiation was found to further enhance this effect. The project also addressed modified ion track-based nanostructures combined with metal nanoparticle/polymer composites. 6 publications in well known peer reviewed international journals are attached to this report and give further details.
Publications
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An ion track based approach to nano- and micro-electronics. Nuclear Instruments and Methods in Physics Research B (NIMB:) 2008, 266, 1642-1646
Hoppe, K.; Fahrner, W.; Fink, D.; Dhamodoran, S.; Petrov, A.; Chandra, A.; Saad, A.; Faupel, F.; Zaporojtchenko, V.; Chakravadhanula, V.
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Controlled reduction of size of Ag nanoparticles embedded in teflon matrix by MeV ion irradiation. Nuclear Instruments and Methods in Physics Research B (NIMB:) 2008, 266, 1804-1809
Mishra, Y.; Chakravadhanula, V.; Schürmann, U.; Kumar, H.; Kabiraj, D.; Ghosh, S.; Zaporojtchenko, V.; Avasthi, D.; Faupel, F.
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Equal intensity double plasmon resonance of bimetallic quasi-nanocomposites based on sandwich geometry. Nanotechnology. 2008, 19, 225302
Chakravadhanula, V. S. K. ; Elbahri, M.; Schürmann, U.; Takele, H.; Greve, H.; Zaporojtchenko, V.; Faupel, F.
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Synthesis and Characterization of Ag-Polymer Nanocomposites. Journal of Nanoscience and Nanotechnology. 2010, 10, 2833-2837
Mishra, Y. K.; Mohapatra, S.; Chakravadhanula, V. S. K. ; Lalla, N. P.; Zaporojtchenko, V.; Avasthi, D. K.; Faupel, F.
