Berlin 2024 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 20: Poster II

DS 20.13: Poster

Donnerstag, 21. März 2024, 18:00–20:30, Poster D

Microphase Separation in Thin Films of a Sphere Forming PS-b-PDMS Block-Copolymer — •Janna X. Friebel, Alexander Stratmann, Harikrishnan Venugopal, and Jörg K. N. Lindner — Nanopatterning - Nanoanalysis - Photonic Materials, Department of Physics, Paderborn University, Germany

According to the bulk phase diagram by Bates et al. [1], block-copolymers (BCP) with a combined Flory-Huggins-parameter χN >10 can form ordered nanostructures even with small degrees of polymerization (N), enabling sub-10nm nanostructures suitable for applications like nanomasks in microelectronics [2]. However, the bulk phase diagram is not applicable to thin films because of interfacial energy effects.

This investigation focuses on BCP thin films of PS-b-PDMS with a high χ and NB/NA ≈ 0.25, expected to form a bulk-state bcc arrangement of PDMS spheres in a PS matrix. Spin-coated onto Si substrates with native oxide films, the films undergo microphase separation in a solvent vapor atmosphere. After etching of the PS phase, AFM and SEM investigations reveal lamellar structures or cylinders oriented parallel to the surface. The morphology of these features and their arrangements are observed to be highly sensitive to slight changes in layer thicknesses and annealing conditions.

[1] F. S. Bates et al., Physics Today 52 (1999) 32-38.

[2] Y. Chen, S. Xiong, Int. J. Extrem. Manuf. 2 (2020) 032006.

Keywords: Block-copolymers; Thin films; Microphase separation; Nanostructure morphology; PS-b-PDMS