Laser-induced forward transfer of soft material nanolayers with millisecond pulses shows contact-based material deposition

• Published in: Applied surface science Vol. 508; p. 144973
• Main Authors: Paris, Grigori, Klinkusch, Andreas, Heidepriem, Jasmin, Tsouka, Alexandra, Zhang, Junfang, Mende, Marco, Mattes, Daniela S., Mager, Dario, Riegler, Hans, Eickelmann, Stephan, Loeffler, Felix F.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-04-2020
• Subjects: Experimental and numerical prediction; Fluorescence imaging; High-speed imaging; OpenFOAM; Vertical scanning interferometry; OpenFOAM; Experimental and numerical prediction; Fluorescence imaging; High-speed imaging; Vertical scanning interferometry
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2019.144973

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•High-speed imaging shows contact-based deposition mechanism.•Quantification of the free surface expansion and relaxation during the combinatorial laser-induced forward transfer.•Numerical prediction of the maximum surface expansion upon laser irradiation.
In this work, we present a qualitative and quantitative experimental analysis, as well as a numerical model, of a novel variant of the laser-induced forward transfer, which uses millisecond laser pulses.
In this process, soft material nanolayer spots are transferred from a donor slide, which is coated with the soft material layer, to an acceptor slide via laser irradiation. This method offers a highly flexible material transfer to perform high-throughput combinatorial chemistry for the generation of biomolecule arrays.
For the first time, we show visual evidence that the main transfer mechanism is contact-based, due to thermal surface expansion of the donor layer. Thus, the process is different from the many known variants of laser-induced forward transfer. We characterize the maximum axial surface expansion in relation to laser power and pulse duration. On this basis, we derive a numerical model that approximates the axial surface expansion within measurement tolerances. Finally, we analyze the topology of the transferred soft material nanolayer spots by fluorescence imaging and vertical scanning interferometry to determine width, height, and shape of the transferred material. Concluding from this experimental and numerical data, we can now predict the amount of transferred material in this process.