Reprint of: Combining theory and experiment for X-ray absorption spectroscopy and resonant X-ray scattering characterization of polymers

Abstract

An improved understanding of fundamental chemistry, electronic structure, morphology, and dynamics in polymers and soft materials requires advanced characterization techniques that are amenable to in situ and in operando studies. Soft X-ray methods are especially useful in their ability to non-destructively provide material or chemical moiety specific information. Analysis of these experiments, which can be very dependent on X-ray energy and polarization, can quickly become complex. Complementary modeling and predictive capabilities are required to properly probe these critical features. Here, we present relevant background on this emerging suite of techniques. We focus on how the combination of theory and experiment has been applied and can be further developed to drive our understanding of how these methods probe relevant chemistry, structure, and dynamics in soft materials.

Probing morphology and chemistry in complex soft materials with in situ resonant soft x-ray scattering

“…RSoXS is promising to enable a glimpse into these complex structures with unprecedented details. With the high coherent power of future diffraction limited storage ring, resonant x-ray scattering combined with chemical x-ray photon correlation spectroscopy (C-XPCS), can allow monitoring the dynamics of the microphases or hierarchical mixture of complex materials with much faster time regime, since the fastest time accessible in XPCS scales as inverse square of coherent intensity [120,121]. Access to faster temporal regime will enable a deeper understanding of material systems away from equilibrium or near the onset of more complex dynamical heterogeneities in complex materials.…”

New Insights into Water Treatment Materials with Chemically Sensitive Soft and Tender X-rays

“…Element-specific XAS provides sensitivity to specific chemical bonds and functional groups. When guided by firstprinciples predictions [34,35], XAS can characterize specific molecular interactions.…”

“…The chemical sensitivity of RXS would likely allow new insights into the independent formation rates of external versus internal fouling. Coherent X-ray scattering methods, including X-ray photon correlation spectroscopy (XPCS) are capable of probing polymer chain dynamics and diffusion in nanostructured systems like block copolymers [35,47]. Future synchrotron upgrades to diffraction-limited storage rings will greatly enhance XPCS capabilities.…”

π‐Conjugated Donor Polymers: Structure Formation and Morphology in Solution, Bulk and Photovoltaic Blends

“…As the absorption fine structure of a chemical species strongly depends on its chemical environment, the refractive index of different materials can be tuned by changing the X-ray energy. [158] As a consequence, such technique allows for contrast matching. Using GI-RSoXS one differentiates between the different scattering contributions in complex active layers with more than two components.…”

“…While the interaction of hard X‐rays (used in conventional GISAXS) with matter is mainly described by the local electron density, the interaction with soft X‐rays is also strongly dominated by the enhanced electron scattering cross section close to the resonant energies (resonant soft X‐ray scattering, RSOXS). As the absorption fine structure of a chemical species strongly depends on its chemical environment, the refractive index of different materials can be tuned by changing the X‐ray energy . As a consequence, such technique allows for contrast matching.…”