New Mexico Consortium Scientist Rex Hjelm Presents at Oak Ridge National Laboratory Workshop
New Mexico Consortium Scientist Rex Hjelm Presents at Oak Ridge National Laboratory Workshop
New Mexico Consortium scientist Dr. Rex Hjelm gave an invited presentation of his research at the workshop “Determining the Needs and Challenges of Isotopically Labeled Soft Materials,” held April 27–29, 2026, at Oak Ridge National Laboratory (ORNL). His presentation, titled “Contrast as a Powerful Tool for Mitigating the Ambiguous Interpretation of Scattering Data,” explored how specialized labeling techniques help scientists better understand the structure of complex materials.
Soft materials, such as polymers, biological molecules, gels, and complex fluids, are essential in fields ranging from medicine and energy storage to advanced manufacturing. Scientists often study these materials using scattering techniques, where beams of X-rays or neutrons are directed at a sample to reveal information about its internal structure. However, interpreting scattering data can be challenging because many different structures can produce similar signals.
Dr. Hjelm’s work focuses on overcoming this challenge through the use of “contrast,” a technique that allows specific parts of a material to stand out more clearly during experiments. One of the most powerful approaches involves replacing hydrogen atoms with deuterium, a heavier isotope of hydrogen to leveraging the strong difference in neutron scattering between the isotopes. This change makes selected components easier to distinguish in neutron scattering experiments without significantly altering the material itself.
By selectively labeling materials with deuterium, researchers can isolate and examine individual structures within highly complex systems. These methods have become especially important in polymer physics and structural biology, where they help scientists test theories, confirm models, and better understand how materials behave at the molecular level.
During the workshop, Dr. Hjelm highlighted how contrast variation and isotopic labeling are used in small-angle neutron scattering (SANS) and neutron reflectometry studies to reveal details that would otherwise remain hidden. Examples included studies of polymers as melts and biological systems, where carefully designed contrast conditions provide quantitative insight into structure, morphology, and uniformity.
Dr. Hjelm also discussed how decades of advances in isotopic labeling have created growing demand for specialized facilities capable of producing deuterated materials. The workshop brought together experts from across the soft matter and neutron science communities to identify future needs and opportunities for developing these critical research capabilities.
His presentation emphasized that isotopic labeling remains one of the most effective tools for reducing uncertainty in scattering experiments and continues to play a vital role in advancing materials science, chemistry, and biology.
To learn more see the entire presentation at: “Contrast as a Powerful Tool for Mitigating the Ambiguous Interpretation of Scattering Data.”