Characterization of As-Prepared Polymeric Films by Simultaneously Measuring the Glass Transition, Crystallinity, and Order-Disorder Transition through the Restitution

The glass transition temperature (T_g) and degree of crystallinity (X_c) are important properties of polymers, and the order-disorder transition temperature (T_ODT) is another important property to characterize block copolymers (BCPs). However, conventional techniques have some inconveniences in measuring these properties at the same cycle of measurement. Thus, we developed a new intuitive technique to simultaneously measure the T_g, X_c, and T_ODT by measuring the restitution of a ball on intact polymeric films based on the Hertz contact theory and rheology. With various types of polymers, including BCPs and conjugated polymers, we showed that T_g can be determined by the onset of the decrease in restitution, X_c is the normalized minimum restitution for X_c up to 50%, and T_ODT is related to another dramatic restitution decreasing point at higher temperatures. All the measured T_gs and X_cs by the ball collision method matched well with the theoretical and/or well-known values measured by the conventional techniques (differential scanning calorimetry, X-ray diffraction), and measured T_ODTs were also compared with the values from dynamic mechanical analysis and/or X-ray scattering. Furthermore, an approach to measuring the sub-micrometer-thick films will be discussed.