Abstract
Ultrathin films of polysiloxane block copolymers and their composites with a C60 modifying additive were studied by atomic force microscopy. Nanometer scale surface patterns independent of the additive concentration were revealed in the surface profiles of the films. These patterns were attributed to the spatial distribution of rigid block domains at the block copolymer surface. Reliable quantitative data on mechanical properties of the films were obtained in indentation tests with specially fabricated spherical probes with a calibrated submicrometer radius of curvature. It was found that the addition of C60 in an amount on the order of 0.01% significantly improves the elasticity of the block copolymer surface layers. At this concentration, several fullerene molecules can be introduced into each nanodomain of rigid blocks.
Acknowledgments
The study was supported by the RFBR (grant 09-01-00623-a), RFNSh scientific school (grant 3306.2010.2), CARL ZEISS, and Umnik project.