SIRIUS-DIMBOTER: A Synchrotron In Situ Research Instrument for Uniaxial Stretching in Diverse Immersion Media across a Broad Temperature Range

Abstract In situ tracking of microstructural evolution during deformation is important for understanding the molecular origin of nonlinear mechanics in soft matter, including synthetic polymers and natural biopolymers. Synchrotron radiation X-ray scattering (SRXS) is well suited for obtaining such information. To mimic real service conditions, various in situ stretching instruments have been developed for installation at SRXS beamlines. However, most existing instruments cannot perform in situ measurements in multiple immersion media, such as air, water, and silicone oil, over a broad temperature range. Here, we present a Synchrotron In Situ Research Instrument for Uniaxial Stretching in Diverse Immersion Media across a Broad Temperature Range (SIRIUS-DIMBOTER), which enables simultaneous mechanical and structural characterization in diverse immersion media over an overall accessible temperature range of 0−200 °C. The deformation mechanism of poly(vinyl alcohol) (PVA) hydrogel films is studied as a demonstration. By performing uniaxial deformation of the hydrogel in water and silicone oil, different structural evolution pathways in the two media can be captured by SRXS. Both mass and heat exchange occur in water (open system), whereas mass transport is suppressed in silicone oil (closed system). SIRIUS-DIMBOTER is expected to facilitate the direct elucidation of the structural origin of nonlinear mechanics in soft matter.