If you look at ice crystals that form on your window during the winter, you see something similar to what you see here. The ice crystallizes from a central point and grows outward into beautiful radial patterns. A similar behavior is seen in polymers that are cooled to a temperature where they can crystallize. The size of the crystalline structures is usually small, but with an optical microscope light, you can see them. If the light is polarized, like passing through polarized sunglasses, you see areas that are bright as well as dark. These areas tell you how the polymers are arranged. Here, an unusual crystallization of a block copolymer was studied where the different blocks crystallized at different temperatures. The bands arise from the crystals twisting like a barber pole from the central point.
Visit Website | Image credit: VISUAL, Materials Research Science and Engineering Center, University of Massachusetts, Amherst