Structural dependency of polymer dynamics by means of small-angle X-ray photon correlation spectroscopy and wide-angle X-ray scattering on the D2AM beamline.

Abstract

X-ray photon correlation spectroscopy (XPCS) has become a pivotal technique for exploring nanoscale dynamic phenomena across various materials, facilitated by advancements in synchrotron radiation sources and beamline upgrades. The recent Extremely Brilliant Source (EBS) upgrade at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France, has notably improved brilliance and coherence length, thereby enhancing the capabilities of XPCS and related techniques. Here, we present a dedicated setup on the D2AM beamline at the ESRF, enabling simultaneous XPCS and wide-angle X-ray scattering measurements. The setup developed and its performance are detailed in the first part. Then, the XPCS capabilities are evaluated by studying polymer-based materials, with particular attention to the effects of temperature, crystallinity and macromolecular orientation on polymer dynamics. The study on the influence of temperature revealed that XPCS in the case of entangled polymers is an efficient technique to probe the dynamics of the macromolecular network, complementary to classical spectroscopy techniques. In addition, in situ measurements during the polymer crystallization revealed that increased crystallinity slows down macromolecular dynamics. Conversely, studies on stretched samples indicate that macromolecular orientation accelerates these dynamics. This work represents a novel investigation into the effect of crystallinity on macromolecular dynamics using XPCS, opening new avenues for research in polymer science.