Macromolecules, Vol.28, No.24, 8006-8015, 1995
Optically-Active Polyethers .2. Atomic-Force Microscopy of Melt-Crystallized Poly(Epichlorohydrin) Enantiomers and Their Equimolar Blend
The surface morphologies of melt-crystallized spherulites of the optically active R and S forms of poly(epichlorohydrin) and their equimolar blend have been investigated by atomic force microscopy (AFM). For the banded spherulites formed from the optically pure polyenantiomers, a regular pattern of alternating concentric ridges and valleys observed by AFM corresponds directly to the pattern of birefringent extinction bands observed under the polarized light microscope. Examination of the surface topography of these banded spherulites, either by reflectance optical microscopy or by AFM, reveals a spiral form with a "sense" or handedness that is dependent on the chirality of the constituent polyenantiomer. In contrast, a relatively featureless surface is observed for the spherulites formed upon crystallization of the equimolar blend. AFM images of the spherulitic surface indicate the presence of predominantly flat lamellae in the equimolar blend while those of the pure polyenantiomer appear to have an alternating flat to edge-on orientation, corresponding to the banding pattern. These observations are discussed in the context of the current theories of lamellar organization in banded spherulites.
Keywords:ISOTACTIC POLYPROPYLENE;POLY(VINYLIDENE FLUORIDE);POLY(ETHYLENE SEBACATE);SINGLE-CRYSTALS;LIQUID SELENIUM;POLYETHYLENE;MORPHOLOGY;POLYMORPHISM;ORIENTATION;BEHAVIOR