Fraunhofer Institute for Microstructure of Materials and Systems IMWS
Nanomaterials have become indispensable in modern products – but determining their exact particle size distribution has been a costly and time-consuming process until now. In the new “UltraSep” project, the Fraunhofer Institute for Microstructure of Materials and Systems IMWS and GAMPT mbH are developing an ultrasound-assisted separation tool that makes electron microscopes usable as an efficient analysis tool for nanopowders. This allows for the fast, precise characterization of nanoparticles – from material development in the laboratory to verification for regulatory requirements.
Nanoparticles determine the properties of many products in electronics, medicine, cosmetics and energy technology – and are also the focus of regulatory requirements. For a reliable classification as a nano or non-nano material, a number-based particle size distribution over a wide size range is required.
Today, screening methods such as dynamic light scattering dominate. Although these techniques are fast, they are very sensitive to agglomerates and, in addition, the particle size is only determined indirectly via model assumptions. Electron microscopy is considered the gold standard but often fails due to overlapping particles and the high manual evaluation effort required. “With the “UltraSep“ project, we are closing the gap between fast screening methods and electron microscopy, which is very accurate but has been slow until now,” says project manager Dr. Katrin Thieme from Fraunhofer IMWS.
Ultrasound creates interference-free particle distributions
This is exactly where “UltraSep” comes in: A newly developed ultrasonic separator breaks up agglomerates in dry powders and dispersions and distributes the particles in such a way that superposition-free 2D particle distributions are created. The frequency, intensity, and excitation pattern of the ultrasound are specifically varied to separate nanoparticles ranging from a few nanometers to the double-digit micrometer range.
GAMPT is developing an ultrasonic generator, suitable actuators, and sample holders that can be integrated directly into the preparation and analysis workflows. At Fraunhofer IMWS, the process is validated using scanning electron microscopy and AI-supported image evaluation is established: Particles are automatically segmented and characterized in terms of various parameters, such as particle size, the longest and shortest dimensions of a particle, or the aspect ratio, and output as a number-based distribution. This creates a continuous workflow from sample preparation to evaluable statistics.
From prototype to solution for powder manufacturers and processors
The project aims to develop a marketable prototype that can be used to supplement existing electron microscopes – initially by powder manufacturers and processors, for example in the pigment, battery, ceramics or cosmetics industries. Applications range from quality control and the development of new materials to ensuring compliance with regulatory requirements.
“Our goal is a robust tool that can be integrated into existing analysis laboratories without extensive training – from sample preparation to evaluable size distribution,” says Katrin Thieme. Validations with reference nanomaterials and tests at industrial partners are intended to ensure that “UltraSep” fits seamlessly into production and laboratory environments, where it will provide greater transparency, safety, and efficiency in nanoparticle analysis.
(February 3, 2026)