Berlin 2005 – scientific programme

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CPP: Chemische Physik und Polymerphysik

CPP 5: SYMPOSIUM: Dynamics of multi-component fluids POSTER

CPP 5.32: Poster

Friday, March 4, 2005, 17:15–19:00, Poster TU D

Scanning Probe Microscopy of Block Copolymer Phase Separation: Force Modulation vs. Tapping Mode — •Daniel Podzimek, Hendrik Hähl, Oliver Bäumchen, Armin Nagel, and Karin Jacobs — Saarland University, POB 151 150, D-66041 Saarbrücken

Microdomain ordering due to the phase separation of incompatible blocks of polymers in thin films can be studied by scanning probe microscopy (SPM). Typically, the different blocks are characterized by different elastic properties which can be revealed by SPM. Commonly, the SPM is used in ’intermittent contact mode’. Here, the surface topography is scanned with an oscillating probe that ’taps’ the surface. The oscillation amplitude is used as control signal. This technique is used for different applications, especially for imaging delicate and fragile samples like weakly adsorbed DNA molecules, colloidal particles or surfaces of polymer materials. Another possibility is to use the SPM in ’force modulation mode’. There, the probe exercises a small oscillation in the vertical direction with a frequency that is much higher than the scanning frequency and much lower than the cantilever resonance frequency, while staying in contact with the surface. The amplitude of the cantilever oscillation varies according to the elastic and friction properties of the sample. In this study we evaluate the two modes on thin films of a linear PS/PEP block copolymer.