Dynamic mechanical analysis at the submicron scale

Dynamic mechanical analysis (DMA) is traditionally performed on bulk samples. However, studies of polymer blends would be enhanced if DMA could be applied on a local scale in order to enable a new form of microthermal analysis. Mounting a sample on a vibrating heating stage and observing the resulting amplitude and phase of the motion of an atomic force microscope cantilever allows the local elastic and visco-elastic properties to be studied. It is demonstrated in this article on samples of polyethersulfone/poly (acryonitrile-co-styrene) and polystyrene/poly(methyl methacrylate) (PS/PMMA) blends, and PMMA, PS and polytetrafluoroethylene homopolymers. Images at a specific temperature and spectroscopic data as a function of temperature of (nominally) a single point were collected. Primary and secondary relaxations were detected; the lateral resolution is better than 100 nm. We discuss the promising and limiting aspects of this new technique. (C) 2000 Elsevier Science Ltd. All rights reserved.