Reviewed by Lexie CornerMar 4 2025
Researchers from the University of Cambridge recently demonstrated that ripple, a key property of 2D materials, affects fluid interactions, strength, conductivity, and chemical activity. Understanding the relationship between rippling and defects is crucial for technologies such as energy storage, flexible electronics, nanofluidics, and catalysis. The study was published in Proceedings of the National Academy of Sciences.
Defects in a flexible sheet. Image Credit: Dr. Camille Scalliet
The surface ripples in two-dimensional materials, such as graphene, which is only one atom thick, can be dramatically affected by defects. These defects can even cause the sheet to freeze in place, much like a still image.
Dr. Fabian Thiemann, the first author of the study, is currently a Research Scientist at IBM. He began this research while pursuing his Ph.D. at UCL, the University of Cambridge, and Imperial College London.
While experiments can capture the overall shape of rippled membranes, they struggle to resolve how these structures evolve at the atomic scale over time. Our simulations bridge this gap, allowing us to track the rippling dynamics in detail and uncover the role of microscopic defects in shaping the material’s morphology.
Dr. Fabian Thiemann, Study First Author, University of Cambridge
Frozen Ripples
2D materials are central to technological advancements in areas such as water filtration, high-speed electronics, and ultra-thin flexible displays. However, at the atomic level, surfaces that appear flat are never truly flat. These 2D surfaces contain microscopic ripples that influence their properties.
The researchers used machine learning-based computer models to simulate 2D sheets of graphene and other materials. These models allowed them to examine how different materials, both with and without defects, exhibit rippling behavior. They discovered that defects in the material affect how ripples propagate and, more significantly, cause the membrane to freeze and lose its flexibility when defect concentrations are high.
The wholescale impact such a small proportion of defects can have on the dynamics of graphene is remarkable. The prospects for exploiting these new fundamental insights are exciting and numerous, particularly in nanofluidics.
Angelos Michaelides, Professor, Yusuf Hamied Department of Chemistry, University of Cambridge
Designing Around Defects
Dr. Camille Scalliet, currently a Permanent Researcher at the Laboratoire de Physique de l'École Normale Supérieure in Paris, conducted this research while serving as a Herchel Smith Postdoctoral Fellow at the University of Cambridge.
She commented: “By understanding how defects influence these ripples, our work helps engineers control the physical behavior of these materials by using defects, something traditionally considered undesirable as a design tool.”
This work is a premier example of how machine learning potentials (a sub-discipline of artificial intelligence) are transforming the field of materials science by enabling more accurate, efficient, and data-driven predictions of material properties. This is accelerating materials discovery and design, leading to the development of novel materials with desired functionalities for various applications.
Erich A Müller, Professor, Department of Chemical Engineering, Imperial College London
The researchers are excited to expand on these findings in the future. Fabian Thiemann and Camille Scalliet discussed their thoughts on the future of their study: “There are great ways to continue this work. Our next steps are to study more complicated situations at the nanoscale, such as membranes in contact with water or other materials. This is just the beginning of this collaboration.”
Journal Reference:
Thiemann, F. L., et al. (2025) Defects induce phase transition from dynamic to static rippling in graphene. Proceedings of the National Academy of Sciences. doi.org/10.1073/pnas.2416932122.