Excimer laser ablation of gold-loaded inverse polystyrene-block-poly (2-vinylpyridine) micelles

• Published in: Applied physics. A, Materials science & processing Vol. 72; no. 6; pp. 679 - 685
• Main Authors: LENGL, G, PLETTL, A, ZIEMANN, P, SPATZ, J. P, MÖLLER, M
• Format: Journal Article
• Language: English
• Published: Berlin Springer 01.06.2001
• Subjects: Applied sciences; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Excimer lasers; Forms of application and semi-finished materials; Gold; Irradiation; Lasers; Materials science; Metals. Metallurgy; Micelles; Nanocomposites; Nanomaterials; Nanoscale materials and structures: fabrication and characterization; Nanostructure; Physics; Polymer industry, paints, wood; Sheets and films; Technology of polymers; Composite film; Gold; Gold complex; Transition metal; Nanostructure; Photochemical reaction; Experimental study; Chemical reduction; Metal cluster; Pyridine(2-vinyl) copolymer; Pulsed laser; Morphology; Diblock copolymer; Chloro complex; Excimer lasers; Laser ablation technique; Reverse micelle; Styrene copolymer
• ISSN: 0947-8396; 1432-0630
• DOI: 10.1007/s003390100762

Diblock-copolymers (PS(1700)-b-P2VP(450) or PS(1350)-b-P2VP(400)) forming spherical micelles, can be loaded with a Au-salt and deposited on top of various substrates. Such polymer films have been exposed to a pulsed ArF excimer laser in order to remove the polymer matrix and, in parallel, to chemically reduce the salt into metallic Au nanodots. To analyze this process in detail, it was subdivided into three steps: (a) laser ablation of thick and thin diblock-copolymer films; (b) laser irradiation of Au-salt loaded diblock-copolymer films; and (c) laser irradiation of arrays of metallic Au nanodots. In (a) it was found that a complete removal of the polymer by laser ablation is only possible in air under ambient conditions while identical laser irradiations under vacuum result in a residual layer of approximately 14 nm. Substep (b) revealed a nucleation process of the resulting metallic Au within the micellar core leading to clusters of small Au dots. Furthermore, this substep provided evidence for an asymmetric interplay between the macroscopic temperature of a polymer film during laser treatment and the energy density per laser pulse. In (c) it could be demonstrated that metallic Au nanodots on mica are stable against laser irradiation under conditions leading to a polymer removal.