Research

Size, shape and composition determine the ultimate properties of nanoparticles. Chemical synthesis control enables tailoring these.­­ We synthesize and surface functionalize 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, adsorber and catalyst nano building blocks.

Selected publications: 

Zhang K., Schötz S., Reichstein J., Groppe P., Stockinger N., Wintzheimer S., Mandel K., Libuda J., Retzer T.
Supraparticles for naked-eye H2 indication and monitoring: improving performance by variation of the catalyst nanoparticles
In: The Journal of Chemical Physics (2023)
DOI: 10.1063/5.0135130

Granath T., Mandel K., Löbmann P.
The Significant Influence of the pH Value on Citrate Coordination upon Modification of Superparamagnetic Iron Oxide Nanoparticles
In: Particle and Particle Systems Characterization (2022)
DOI: 10.1002/ppsc.202100279

Granath T., Loebmann P., Mandel K.
Overcoming the Inhibition Effects of Citrate: Precipitation of Ferromagnetic Magnetite Nanoparticles with Tunable Morphology, Magnetic Properties and Surface Charge
via Ferrous Citrate Oxidation
In: Particle and Particle Systems Characterization (2021)
DOI: 10.1002/ppsc.202100098

Granath T., Loebmann P., Mandel K.
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)
DOI: 10.1002/ppsc.202000307

Muendlein M., Schug B., Wintzheimer S., Mandel K.
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
DOI: 10.1016/j.jmmm.2019.165350

Upon droplet evaporation, using the tool spray-drying, forced assembly of nano building blocks to supraparticles is possible. Furthermore, via this method, also molecular precursors and molecules can be joined, i.e., we can also perform “chemistry in a droplet”.

We study how structure, besides composition, of such supraparticles affects the interaction among the building blocks of these entities and how this leads to unique functionalities.

Selected publications:

Wenderoth S., Bleyer G., Endres J., Prieschl J., Vogel N., Wintzheimer S., Mandel K.
Spray-dried photonic balls with a disordered/ordered hybrid structure for shear stress indication
In: Small (2022)
DOI: 10.1002/smll.202203068

Miller F., Wenderoth S., Wintzheimer S., Mandel K.
Rising like a phoenix from the ashes: Fire-proof magnetically retrievable supraparticles with an optical fingerprint for post-mortem identification of products
In: Advanced Optical Materials (2022)
DOI: 10.1002/adom.202201642

Wenderoth S., Eigen A., Wintzheimer S., Prieschl J., Hirsch A., Halik M., Mandel K.
Supraparticles with a mechanically triggerable color-change-effect to equip coatings with the ability to report damage
In: Small (2022)
DOI: 10.1002/smll.202107513

Pujales Paradela R., Granath T., Seufert M. T., Kasper T., Müller-Buschbaum K., Mandel K.
Luminescent magnets: hybrid supraparticles of a lanthanide-based MOF and ferromagnetic iron oxide by assembly in a droplet via spray-drying
In: Journal of Materials Chemistry C (2022)
DOI: 10.1039/D1TC04867H

Müssig S., Koch V. M., Cuadrado C. C., Bachmann J., Thommes M., Barr M. K. S., Mandel K.
Spray-Drying and Atomic Layer Deposition: Complementary Tools toward Fully Orthogonal Control of Bulk Composition and Surface Identity of Multifunctional Supraparticles
In: Small Methods (2021)
DOI: 10.1002/smtd.202101296

We believe that supraparticles can be turned into communicating and interactive objects – a vision that we would like to become reality. Particles are developed that carry unique IDs, are able to perceive and subsequently report environmental stimuli, and can transform their state – which includes principles of micro reactor / micro ecosystems in a particle.

Selected publications:

Wenderoth S., Müssig S., Prieschl J., Genin E., Heuzé K., Fidler F., Haddad D., Wintzheimer S., Mandel K.
Optically sensitive and magnetically identifiable supraparticles as indicators of surface abrasion
In: Nano Letters (2022)
DOI: 10.1021/acs.nanolett.1c04773

Reichstein J., Schötz S., Macht M., Maisel S., Stockinger N., Cuadrado Collados C., Schubert K, Blaumeiser D., Wintzheimer S., Görling A., Thommes M., Zahn D., Libuda J., Bauer T., Mandel K.
Supraparticles for Bare-Eye H2 Indication and Monitoring: Design, Working Principle, and Molecular Mobility
In: Advanced Functional Materials (2022)
DOI:10.1002/adfm.202112379

Miller F., Reichstein J., Mandel K.
Hybrid inorganic-organic luminescent supraparticle taggants with switchable dual-level ID
In: Advanced Optical Materials (2022)
DOI: 10.1002/adom.202102520 

Müssig S., Reichstein J., Miller F., Mandel K.
Colorful Luminescent Magnetic Supraparticles: Expanding the Applicability, Information Capacity and Security of Micron-scaled Identification Taggants by Dual-Spectral Encoding
In: Small (2022)
DOI: 10.1002/smll.202107511

Reichstein J., Miller F., Wintzheimer S., Mandel K.:
Communicating Particles: Identification Taggant and Temperature Recorder in One Single Supraparticle
In: Advanced Functional Materials (2021)
DOI: 10.1002/adfm.202104189

Joining different nano building blocks to supraparticles is particularly interesting for adsorber and carrier systems. Firstly, porous systems can be generated (via interstitial and/or templated pore formation). Secondly, besides chemical adsorber affinity / carrier design, further functionality addition is possible such as magnetic properties for separation or inductive heatability of the system.

Selected publications:

Schneider M., Tschoepe A., Hanselmann D., Ballweg T., Cehermann C., Franzreb M., Mandel K.
Adsorber Particles with Magnetically-Supported Improved Electrochemical Conversion Behavior for Waste Water Treatment Processes
In: Particle & Particle Systems Characterization 37 (2020), Article No.: 1900487
DOI: 10.1002/ppsc.201900487

Tschöpe A., Heikenwälder S., Schneider M., Mandel K., Franzreb M.
Electrical conductivity of magnetically stabilized fluidized-bed electrodes – Chronoamperometric and impedance studies
In: Chemical Engineering Journal 396 (2020)
DOI: 10.1016/j.cej.2020.125326

Schneider M., Ballweg T., Gross L., Cellermann C., Sanchez-Sanchez A., Fierro V., Ceizard A., Mandel K.
Magnetic Carbon Composite Particles for Dye Adsorption from Water and their Electrochemical Regeneration
In: Particle & Particle Systems Characterization 36 (2019), Article No.: 1800537
DOI: 10.1002/ppsc.201800537

Oppmann M., Wozar M., Reichstein J., Mandel K.
Reusable Superparamagnetic Raspberry-Like Supraparticle Adsorbers as Instant Cleaning Agents for Ultrafast Dye Removal from Water
In: ChemNanoMat 5 (2019), p. 230-240
DOI: 10.1002/cnma.201800490

Drenkova-Tuhtan A., Schneider M., Franzreb M., Meyer C., Gellermann C., Sextl G., Mandel K., Steinmetz H.
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
DOI: 10.1016/j.watres.2016.11.039

Supraparticles can provide an emergent, tunable porosity and precisely configurable accessibility of active catalyst sites, thus, enhanced catalytic activity and stability. Their flexible setup also permits the integration of multiple different building blocks, which allows for coupling interactions within the material, e.g., energy transfers, or the addition of further functionalities such as an inductive heatability of the systems. For the direct application of supraparticles in catalytic fixed-bed reactors, their attachment on beads, yielding ‘suprabeads’, is a strategy to increase their size regime without compromising their unique supraparticle-based functionality.

Selected publications:

Iron oxide-based nanoparticles can be engineered to be magnetically steerable, inductively heatable or chemically reactive. Joined to entites such as supraparticles, collective magnetic interaction occurs. Besides designing these magnetic interactions, we also study them via the method of magnetic particle spectroscopy (MPS) that we pioneer and consider as a very powerful tool that provides new eyes to study processes or materials when it is dark, i.e., when one cannot use (light) optical means.

Selected publications:

Groppe P., Wintzheimer S., Eigen A., Gaß H., Halik M., Mandel K.
Real-time Monitoring of Magnetic Nanoparticles-assisted Nanoplastic Removal from Water
In: RSC Environmental Science: Nano (2022)
DOI: 10.1039/D2EN00131D

Reichstein J., Müssig S., Bauer H., Wintzheimer S., Mandel K.
Recording Temperature with Magnetic Supraparticles
In: Advanced  Materials (2022)
DOI: 10.1002/adma.202202683

Müssig S., Reichstein J., Prieschl J., Wintzheimer S., Mandel K.
A Single Magnetic Particle with Nearly Unlimited Encoding Options
In: Small (2021)
DOI: 10.1002/smll.202101588

Müssig S., Kuttich B., Fidler F., Haddad D., Wintzheimer S., Kraus T., Mandel K.
Reversible magnetism switching of iron oxide nanoparticle dispersions
by controlled agglomeration
In: Nanoscale Advances 3 (2021), p. 2822-2829
DOI: 10.1039/d1na00159k