Oriented poly(dialkylstannane)s

The inorganic (or ‘organometallic’) polymers poly(dibutylstannane), poly(dioctylstannane), and poly(didodecylstannane) have been oriented by shear forces, the tensile drawing of blends with polyethylene, and deposition from solution onto glass slides coated with an oriented, friction-deposited poly(tetrafluoroethylene) (PTFE) layer. Orientation of the polystannanes has been examined by polarization microscopy, UV-vis spectroscopy with polarized light, and X-ray diffraction and their direction is found to depend on the length of the alkyl side groups and the method of orientation. Remarkably, in some cases the polystannane backbones are oriented parallel and in other instances perpendicular to the direction of the external orientation stimuli. The latter structural arrangement is most conspicuous for polymers substituted with dodecyl side groups, which are found to align parallel to the applied orientation direction, which forces the polymer backbone into a perpendicular position. Finally, UV-vis spectra indicate that changes in the backbone conformation of certain polystannanes might be induced by applying mechanical stress.