Regensburg 2022 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 45: Biopolymers, Biomaterials and Bioinspired Functional Materials (joint session CPP/BP)
CPP 45.6: Talk
Friday, September 9, 2022, 11:00–11:15, H39
Influence of molecular weight of polycation polydimethyldiallylammonium and carbon nanotube content on the electric conductivity of layer-by-layer films — •Sven Neuber1, Annekatrin Sill1, Peter Nestler2, Heiko Ahrens1, and Christiane A. Helm1 — 1Universcity of Greifswald, Institut of Physics, Greifswald, Germany — 2TÜV NORD EnSys GmbH & Co. KG, Greifswald, Germany
For biological and engineering applications, nm-thin films with high electrical conductivity and tunable sheet resistance are desirable. Multilayers of polydimethyldiallylammonium chloride (PDADMA) with two different molecular weights (322 and 44.3 kDa) and oxidized carbon nanotubes (CNTs) were constructed using the layer-by-layer technique. Both the film thickness and the surface coverage of the CNTs increased linearly with the number of CNT/PDADMA bilayers deposited (dfilm up to 80 nm). Atomic force microscopy images showed a predominantly surface-parallel orientation of CNTs. Ohmic behavior with constant electrical conductivity of each CNT/PDADMA film and conductivity up to 4*10^3 S/m was found. A change in PDADMA molecular weight by almost a factor of ten does not affect the film thickness and electrical conductivity, only the film/air roughness is reduced. However, increasing CNT concentration in the deposition dispersion from 0.15 up to 0.25 mg/ml results in an increased thickness of a CNT/PDADMA bilayer (by a factor of three). The increased bilayer thickness is accompanied by a decreased CNT coverage and a decreased electrical conductivity (by a factor of four).