Nanopartikeldispersionen mittels Ultrakurzpuls-Laserstrahlabtragen in Flüssigkeit
Zusammenfassung der Projektergebnisse
The goal of this project was to investigate the principal parameters that affect the nanoparticle generation process by ultrashort-pulsed laser ablation in organic solvents. Former investigations showed that because of the confining effect of the liquid over the target, higher temperatures, pressures and densities are reached in the laser-induced plasma if compared to ablation in gaseous media. The condensation of the ablated matter in the plume and in the liquid environment should determine the final nanoparticle size, morphology and stability. Since the thermodynamic state of the plasma plume is affected by the laser as well as the solvent, careful reflection of the published results is important. We intended to clarify the effect of different parameters on the production rate and particle size distribution by selective experiments on pulse energy, focusing conditions, repetition rate, solvent chemical properties, temperature, stability and agglomeration kinetics… During our investigations, we realized that direct transfer of results and trends from laser ablation in gas atmosphere to laser ablation in liquids is rarely possible. The process in liquids presents relevant features (confinement, enhanced plume shielding, cavitation…) that should be and have been considered within this project. In order to study the generation process without screening co-effects during the laser ablation, we have introduced the ablation in liquid flow. Hence, higher productivities and direct influence on particle size distribution were achieved. Using this ablation method, we could confirm that particle size correlates with the irradiated spot on the target while pulse energy directly relates to ablation rate. The effect of the repetition rate of laser pulses on the ablation process (abation rate and efficiency) and resulting particle size distribution has been investigated. The result of our experiments indicated the proper processing parameters (wavelength, fluence, scanning velocity, repepetition rate, ablation pattern…) that should be used for the efficient generation of nanoparticles in liquids. We have achieved a remarkable productivity escalation considering the knowledge acquired in this research period. Up to 0.3 g/h nanomaterial can be generated by laser ablation in liquids [Bar2,P7], which by the typical fill factor of 0.1 wt% silver for antibacterial nanocomposites, will lead to 3 kg/h functional polymer. The comparison between different liquids and solutions of molecules in organic solvents led to the finding that complex interactions take place during and after the formation of nanoparticles. Laser parameters and characteristics of the ablation completely differ from each other at the same experimental conditions for different liquids, due to the distinct propagation of the beam and expansion of the plume. These factors have been also considered and studied for a better reproducibility of the experiments. A parametrization of the experimental set-up (based on liquid optical properties and laser focusing conditions) has been done in order to anticipate disadvantageous ablation streams. Kinetic studies done on stabilization and particle coating have shown a linear relation of shell thickness with reaction time, which allows a perfect customization of optical properties of the coated particles. With this new background, the quality (size, polydispersity, stability) and quantity (ablation rate and efficiency) of nanoparticles generated by laser ablation in liquids is improved. The nanoparticle dispersions offered to other disciplines (biotechnology, medicine, environmental science…) are hence better characterized. Fundamental and applied research in nanoscience, as well as industry and development, will profit from the results achieved.
Projektbezogene Publikationen (Auswahl)
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Electrophoretic deposition of metallic nanoparticles generated by femtosecond laser ablation in liquid media. (Conference CODEF II 2008)
A. Menéndez-Manjón, J. Jakobi, K. Schwabe, J.K. Krauss, S. Barcikowski
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Metallic nanoparticles generated by ultra-short pulsed laser ablation in organic solvents. (Conference PARTICLES 2008)
A. Menéndez-Manjón, A. Hahn, S. Barcikowski
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Mobility of nanoparticles generated by femtosecond laser ablation in liquids and its applications to surface patterning. (LPM 2008)
A. Menéndez-Manjón, S. Barcikowski
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Mobility of nanoparticles generated by femtosecond laser ablation in liquids and its applications to surface patterning. Journal of Laser Micro/Nanoengeniering 4(2), pp.95-99 (2009)
A. Menéndez-Manjón, J. Jakobi, K. Schwabe, J.K. Krauss, S. Barcikowski
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Modeling of fast phase transitions dynamics in metal target irradiated by pico- and femtosecond pulsed laser. Applied Surface Science 255, iss. 10, pp. 5112-5115 (2009)
V.I. Mazhukin, M.G. Lobok, B. Chichkov
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Ultrashort pulse laser propagation in liquids and its application to nanoparticle formation. (LPM 2009)
A. Menéndez-Manjón, S. Barcikowski, B. Chichkov
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Ablation efficiency of a-Al2O3 in liquid phase and ambient air by nanosecond laser irradiation. Applied Physics A, 2009
C.L. Sajti
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Gram Scale Synthesis of Pure Ceramic Nanoparticles by Laser Ablation in Liquid. Journal of Physical Chemistry C, 2009
C.L. Sajti, R. Sattari, B.N. Chichkov, S. Barcikowski
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Influence of beam intensity profile on the aerodynamic particle size distributions generated by femtosecond laser ablation. Particle and Laser Beams, 2009
A.Menéndez-Manjón, S. Barcikowski, G.A. Shafeev, V.I. Mazhukin, B.N. Chichkov
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Influence of Water Temperature on the Hydrodynamic Diameter of Gold Nanoparticles from Laser Ablation. Journal of Physical Chemistry C, 2009
A. Menéndez-Manjón, B.N. Chichkov, S. Barcikowski
