Dresden 2009 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 6: Thin Films
CPP 6.7: Talk
Monday, March 23, 2009, 15:30–15:45, ZEU 160
Single molecule tracing to analyze the surface morphology of block-copolymer thin films — •Mustafa Yorulmaz1, Alper Kiraz1, and Adem Levent Demirel2 — 1Department of Physics, Koç University, Rumelifeneri Yolu, 34450 Sariyer, Istanbul, Turkey — 2Department of Chemistry, Koç University, Rumelifeneri Yolu, 34450 Sariyer, Istanbul, Turkey
Single molecules are sensitive reporters that can provide detailed information on their host matrices. In our studies, Terrylene molecules are embedded in Polybutadiene-Polyethylene Oxide (PB-PEO) block-copolymer thin films which reveal cylindrical channels of PB (diameters of ∼40-80 nm) that are oriented parallel to the substrate inside the PEO matrix[1]. Samples are prepared by spin coating a Terrylene/Toluene (∼20 nM) and PB-PEO/Toluene (∼40 mg/mL) mixture on cover glass. Thin films are then annealed for better channel formation. Terrylene molecules are monitored by using the total internal reflection fluorescence (TIRF) microscopy technique. TIRF microscopy images are then recorded with an Electron Multiplied Charge Coupled Device camera (Hamamatsu-ImagEM). Our experiments revealed single molecule traces matching the thin film morphology observed in AFM images. In some of the traces, single molecules are also observed to switch between parallel cylindrical channels. Mean square displacement curves also revealed parabolic dependences to the lag time, suggesting directed diffusion within the channels. This is attributed to the variations in the channel diameters in those cases. [1] M. Y. Yuce, A. L. Demirel, and F. Menzel, Langmuir 21, 5073-5078 (2005).