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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 21: Poster: Confinement of Polymers in Nanoscopic Layers - How Much do Properties Change?

CPP 21.5: Poster

Dienstag, 15. März 2011, 18:00–20:00, P2

Structure-Property Relationships of Plasma Deposited Poly (acrylic acid) Thin Films — •Alaa Fahmy, Renate Mix, Andreas Schönhals, and Jörg Friedrich — BAM Federal Institute for Materials Research and Testing, Unter den Eichen 87, 12205 Berlin, Germany

Poly (acrylic acid) films with a thickness of about 150 nm were deposited in the pulsed plasma regime onto aluminium and glass substrates. The structure/property relationships of these samples were studied in dependence on the duty cycle (DC) of the plasma by a broad combination of different techniques and probes. For the first time volume sensitive methods (FTIR, dielectric spectroscopy, and differential scanning calorimetry) are combined with surface analytics by employing XPS. For an unambiguous identification of COOH groups by XPS, derivatisation with trifluoroethanol was accomplished. Quantitative FTIR investigations give qualitatively the same dependence of the concentration of COOH groups on DC like XPS investigations. The dielectric measurements reveal that the structure of the plasma deposited films is different from that of the bulk material. Especially a lower glass transition temperature is observed. This result points to a highly branched structure of the plasma deposited polymer with a high number of dangling chains. Moreover, the dielectric measurements show that the plasma deposited films are not thermally stable but undergo a post plasma chemical reaction during heating, where the reaction kinetics depends on DC.