A research group from Chalmers and the MAX IV Laboratory has developed a new method that provides insights into how natural materials, such as wood-based systems, behave across multiple length scales. By combining several advanced techniques, this study opens great possibilities for future material design. The research is published in Advanced Science.
Many natural materials, such as wood-based systems, receive unique properties from being structured in a hierarchical way over several length scales. Nature has evolved to create hierarchical materials composed of structures that span a vast range of dimensions, from molecular to macroscopic organization.
One common example is wood, which is built up by several different layers of structures, starting with cellulose chains that bundle into fibrils, forming fibers that build cell walls and wood tissue, ultimately creating the full tree. This hierarchical structure gives the wood great mechanical properties while at the same time being lightweight, since it is not a block of homogenous material.
By researching natural materials, researchers aim to replicate similar hierarchies in synthetic materials but in a fraction of the time it takes for nature to do so.
First time observing multiple scales simultaneously
A research group from Chalmers and the MAX IV Laboratory has now developed a method that makes it possible to observe how hierarchical materials behave under flow conditions—at multiple length scales at once.
“Previously, we could only observe one scale at a time, which meant losing simultaneity and important details about how the different layers orient in relation to each other,” says Roland Kádár, Professor of Rheology at the Department of Industrial and Materials Science.
The new method, called Rheo-PLI-SAXS, combines three techniques: rheology, polarized light imaging, and small-angle X-ray scattering, the latter involving synchrotron radiation experiments. The method allows researchers to examine materials under flow conditions, specifically in simple shear—a type of deformation where parallel layers of material slide past each other.
The ability to study multiple length scales simultaneously paves the way for significant possibilities in materials science.
“For the first time, we can determine how orientation, which is a most important parameter for material properties, propagates across nano–macro length scales in the hierarchy,” says Kádár.
Unique opportunities at large-scale facilities
The collaboration with the MAX IV Laboratory in Lund, Sweden, has provided a unique environment for developing new techniques and has been a central condition for the development of the Rheo-PLI-SAXS method, according to Kádár.
“The MAX IV Laboratory has led the way in modernizing synchrotron radiation facilities, by providing the most brilliant X-rays for research. This has enabled considering the design of new experiments that could take advantage of the new opportunities,” he says.
In this framework, Chalmers and the MAX IV Laboratory, have embarked in partnership to develop so-called sample environments, which enable researchers to test materials under controlled conditions that can, for example, mimic real-world environments.
“New and innovative sample environments are crucial for providing new insights into matter at nanoscale,” says Dr. Ann Terry, beamline manager for the CoSAXS beamline at the MAX IV Laboratory.
“Our ForMAX beamline has been specifically designed to provide multiscale and multimodal analysis methods for materials from wood,” says Dr. Kim Nygård, beamline manager for the ForMAX beamline at the MAX IV Laboratory.
The partnership between Chalmers and the MAX IV Laboratory has evolved into a Science Initiative at the MAX IV Laboratory through which the group aims to continue the method development work to an even deeper understanding of how materials behave across multiple scales. The continuing work has been part of the FibRe Vinnova Competence Center and the Wallenberg Wood Science Center.
Kádár highlights the significant effort and collaboration required for such demanding experiments. “I am grateful to over two generations of students that have contributed to these developments,” he says.
The Rheo-PLI-SAXS method in short
The Rheo-PLI-SAXS method combines three advanced techniques: rheology, polarized light imaging, and small-angle X-ray scattering. Rheology studies how materials flow and deform under an applied stress or deformation. It is an analytical technique that can be used to characterize the structural evolutions of materials in flow.
Polarized light imaging (PLI) is a technique using visual light to examine the alignment and orientation of a material’s internal structures. Small-angle X-ray scattering (SAXS) studies nanoscale structures, revealing how the smallest structural layers of a material behave.
By using these techniques at the same time, the Rheo-PLI-SAXS method provides a unique level of insight into how the layers of a hierarchical material behave and interact under flow conditions, specifically in simple shear.
This new possibility can contribute to significant understanding of the relationship between the structure of a material and its properties, which paves the way for designing new materials with advanced multifunctional properties.
More information:
Reza Ghanbari et al, Propagation of Orientation Across Lengthscales in Sheared Self‐Assembling Hierarchical Suspensions via Rheo‐PLI‐SAXS, Advanced Science (2024). DOI: 10.1002/advs.202410920
Provided by
Chalmers University of Technology
Citation:
Advanced method reveals how natural materials behave across multiple length scales (2025, January 28)