Research
Research
The Supraparticle Group
We assemble complex particles, so-called supraparticles, from nano building blocks.
We study how the supraparticle’s structure and complex composition determines unique functionalities. With these supraparticles, we aim at creating smart materials in the field of sustainability.
Our research areas in detail:
Wet chemically synthesized nanoparticles with designed properties

Nanoparticles possess characteristic and unique physical / functional properties. Their size, shape and composition determines the ultimate properties. Chemical synthesis control enables tailoring these physical properties. We synthesize and surface functionalize inorganic nanoparticles, in particularly metal oxide nanoparticles, by means of bottom-up wet chemistry and subsequently use these as building blocks to assemble functional supraparticles. A main interest is on magnetic, luminescent and adsorber nano building blocks.
Selected publications:
Oxidative Precipitation as a Versatile Method to Obtain Ferromagnetic Fe3O4 Nano- and Mesocrystals Adjustable in Morphology and Magnetic Properties
In: Particle & Particle Systems Characterization (2021)
ISSN: 0934-0866
DOI: 10.1002/ppsc.202000307
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Facile synthesis of magnetic nanoparticles optimized towards high heating rates upon magnetic induction
In: Journal of Magnetism and Magnetic Materials 488 (2019), Article No.: 165350
ISSN: 0304-8853
DOI: 10.1016/j.jmmm.2019.165350
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Supraparticles with silica protection for redispersible, calcined nanoparticles
In: Nanoscale Advances 1 (2019), p. 4277-4281
ISSN: 2516-0230
DOI: 10.1039/c9na00442d
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Pushing up the magnetisation values for iron oxide nanoparticles: Via zinc doping: X-ray studies on the particle's sub-nano structure of different synthesis routes
In: Physical Chemistry Chemical Physics 18 (2016), p. 25221-25229
ISSN: 1463-9076
DOI: 10.1039/c6cp04221j
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General supraparticle formation: bridging molecular and materials chemistry

We start from synthesizing inorganic nanoparticle building blocks by means of wet chemistry. Via control over the wet chemical synthesis parameters, the size, shape and composition of the nanoparticles, thus their physical properties (e.g. optical or magnetic or adsorber or catalytic properties), can be tailored. From collaboration partners, we obtain further inorganic or organic nano or molecular building blocks.
By means of spray-drying and other methods, we assemble the different building blocks to more complex entities, so-called supraparticles. We study how the assembly process can be influenced to tailor the supraparticles`s composition and structure as this determines the ultimate functional properties of the supraparticle systems.
Selected publications:
Supraparticles for Sustainability
In: Advanced Functional Materials (2021)
ISSN: 1616-301X
DOI: 10.1002/adfm.202011089
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Supraparticles: Functionality from Uniform Structural Motifs
In: ACS nano 12 (2018), p. 5093-5120
ISSN: 1936-0851
DOI: 10.1021/acsnano.8b00873
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Colloidal Core–Satellite Supraparticles via Preprogramed Burst of Nanostructured Micro-Raspberry Particles
In: Particle & Particle Systems Characterization 35 (2018), Article No.: 1800096
ISSN: 0934-0866
DOI: 10.1002/ppsc.201800096
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Hollow Superparamagnetic Microballoons from Lifelike, Self-Directed Pickering Emulsions Based on Patchy Nanoparticles
In: ACS nano 10 (2016), p. 10347-10356
ISSN: 1936-0851
DOI: 10.1021/acsnano.6b06063
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Communicating particles

One major focus of our current research is on creating supraparticles which carry a unique ID, i.e., which possess a fingerprint.
Installing an ID in one single particle is achieved by assembling supraparticles from nano building blocks with well-defined physical properties in specifically defined ratios. We do this either with optical or magnetic systems. Furthermore, we equip particles with monitoring or recording functionalities. Our ultimate aim is to create „communicating particles“ which can be employed to track processes, keep materials in use, trace material components and enable smart recycling approaches.
Selected publications:
Communicating Particles: Identification Taggant and Temperature Recorder in One Single Supraparticle
In: Advanced Functional Materials (2021)
DOI: 10.1002/adfm.202104189
A Single Magnetic Particle with Nearly Unlimited Encoding Options
In: Small (2021)
DOI: 10.1002/smll.202101588
Luminescent Supraparticles Based on CaF2-Nanoparticle Building Blocks as Code Objects with Unique IDs
In: ACS Applied Nano Materials 3 (2020), p. 734-741
DOI: 10.1021/acsanm.9b02245
Expanding the Horizon of Mechanochromic Detection by Luminescent Shear Stress Sensor Supraparticles
In: Advanced Functional Materials 29 (2019), Article No.: 1901193
ISSN: 1616-301X
DOI: 10.1002/adfm.201901193
Adsorber supraparticles for purification and sensing

We aim at designing supraparticles which can be added to fluids and interact specifically with target substances in these fluids. The ultimate goal is either an adsorption of the target substance onto the particle`s surface, or an interaction of the target substance with the building blocks of the supraparticles. As a result, as the particles typically also possess magnetic properties, target substances can either be removed and recovered from the fluid with the help of the supraparticles, or the supraparticles act as detectors and indicate the presence and concentration of the target substance.
Selected publications:
Reusable Superparamagnetic Raspberry-Like Supraparticle Adsorbers as Instant Cleaning Agents for Ultrafast Dye Removal from Water
In: ChemNanoMat 5 (2019), p. 230-240
ISSN: 2199-692X
DOI: 10.1002/cnma.201800490
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Pilot-scale removal and recovery of dissolved phosphate from secondary wastewater effluents with reusable ZnFeZr adsorbent @ Fe3O4/SiO2 particles with magnetic harvesting
In: Water Research 109 (2017), p. 77-87
ISSN: 0043-1354
DOI: 10.1016/j.watres.2016.11.039
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Superparamagnetic Luminescent MOF@Fe3O4/SiO2 Composite Particles for Signal Augmentation by Magnetic Harvesting as Potential Water Detectors
In: ACS Applied Materials and Interfaces 8 (2016), p. 5445-5452
ISSN: 1944-8244
DOI: 10.1021/acsami.5b11965
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Interactive surfaces enabled by supraparticles

Supraparticles are considered as key to equip surfaces with interactive functionalities. We aim at creating surfaces that can optically indicate external influences (for example create surfaces that change color upon encounter of a target gas or upon shear stress) or whose surface properties can be switched (for example create a surface which can change its color or its temperature upon a magnetic switching event, or witch can catch and release substances).
Selected publications:
A Supraparticle-Based Five-Level-Identification Tag That Switches Information Upon Readout
In: Advanced Optical Materials (2020)
ISSN: 2195-1071
DOI: 10.1002/adom.202001972
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Indicator Supraparticles for Smart Gasochromic Sensor Surfaces Reacting Ultrafast and Highly Sensitive
In: Particle & Particle Systems Characterization 36 (2019), Article No.: 1900254
ISSN: 0934-0866
DOI: 10.1002/ppsc.201900254
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Smart Surfaces: Magnetically Switchable Light Diffraction through Actuation of Superparamagnetic Plate-Like Microrods by Dynamic Magnetic Stray Field Landscapes
In: Advanced Optical Materials 6 (2018), Article No.: 1800133
ISSN: 2195-1071
DOI: 10.1002/adom.201800133
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Coatings with a Mole-hill Structure of Nanoparticle-Raspberry Containers for Surfaces with Abrasion-Refreshable Reservoir Functionality
In: ACS Applied Materials and Interfaces 7 (2015), p. 24909-24914
ISSN: 1944-8244
DOI: 10.1021/acsami.5b08380
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