Thermo-mechanical properties in hyperbranched polystyrene (HBPS) films were studied by dynamic mechanical analysis (DMA). The samples for DMA were spin-coated from toluene solutions onto polyimide film (PI) substrates. In case of the proton-terminated HBPS (HBPS-H) film with the thickness of about 400 nm, the αa-absorption peak corresponding to the segmental motion appeared at a temperature lower than that for the corresponding linear PS film due mainly to the large number density of chain ends. As the HBPS-H film became thinner than about 70 nm, the αa-absorption peak became broader than that for the thicker one because of the contribution from the free surface and the substrate interface. Moreover, the αa-relaxation temperature for the HBPS films with dithiocarbamated end groups further decreased, indicating that thermal molecular motion in HBPS films could be controlled by chain end chemistry.
|Number of pages||2|
|Publication status||Published - Dec 1 2006|
|Event||55th Society of Polymer Science Japan Symposium on Macromolecules - Toyama, Japan|
Duration: Sep 20 2006 → Sep 22 2006
|Other||55th Society of Polymer Science Japan Symposium on Macromolecules|
|Period||9/20/06 → 9/22/06|
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