Unraveling metastable nanostructures of isotactic polypropylene on solids

Owing to strong demands for newly emerging polymer-based nanotechnologies, many sophisticated devices are moving towards nanometer scales, while maintaining exceptional performance capabilities. The key to breakthroughs in such advanced polymer-based technologies is a better understanding of a solid-polymer melt (SPM) interface which determines their stability/reliability and properties/functionalities. In this talk, we focus on substrate-induced heterogeneous nanostructures of semicrystalline polymers that exist on solid surfaces even above the bulk melting temperatures. Isotactic polypropylene (iPP) and two different planar substrates, i.e., silicon and carbon-layer (~ 20 nm thick) coated silicon substrates were used as rational models. The SPM interfaces were exposed to the air by solvent rinsing of supported iPP thin films (about 100 nm thick) thoroughly. In-situ grazing incidence small-angle X-ray scattering and X-ray diffraction measurements were performed to study the temperature dependence of the crystalline and lamellar structures at the SPM interface. The details will be discussed in the presentation.