Research Focus



Polymer materials have made our life comfortable; they have also contributed to prolong it. One type of such materials are polymer networks and gels, and a particularly promising sub-type of these are active polymer gels. These are soft materials with adaptive action, whose function is based on non-covalent binding in the gel network, either in a sense of transient chain connectivity or in a sense of delicate interactions of the chains with their environment. Both modes of action can serve in various advanced applications in which a gel specimen serves to adapt its degree of swelling, its viscoelasticity, and its permeability in response to external parameters. To make this all truly useful, though, it is necessary to understand the mutual interplay between (nano)structure, dynamics, and properties of these fascinating materials.



This endeavor has been in our group’s focus for decades.

At the same time, our world witnessed increasing impacts of the most dangerous threat in mankind's history: the climate crisis.

Whereas polymer materials, including networks and gels, are stereotypes of the 20th century one-way economy that led into this crisis, they also have excellent promise to contribute to addressing our present climate and resource crises. There's two areas for that.

First, polymer gels have promise to help in adapting to climate-crisis consequences. For example, charged sensitive hydrogels that are active and switchable can serve to purify, detox, and desalinate water to ensure supply with this essential resource. Second, polymer-network materials that are interlinked non-covalently have prospect to be fully recyclable, thereby paving path to transform essentials such as rubbers and superabsorbers into a cyclic economy.


Our research is centered around these two areas. We target at the elementary understanding of the interplay of (nano)structure, dynamics, and properties of active and supramolecular polymer networks and gels such to develop material concepts for the two fields. With that, our work aims at contributing to make the 21st century the age in which mankind transformed its materials economy such to ensure a livable, lasting, and lovely planet.

In  the  first area  of our  current  and  prospective research, we're  central and leading part of an international network  of  research groups from  Mainz, Tehran, Bushehr, and  Bagdad named 'HydroDeSal'. Our goal is to develop  thermo-sensitive charged gels that can act as both draw-agents and semi-permeable membranes in forward  osmosis  processes,  driven  by  the  natural  temperature oscillation of Earth's day-and-night cycle. Together with  engineers  from  the  Fraunhofer Institute for Microengineering and Microsystems, we target at developing  a  lab demonstrator  setup  that  is able  to purify and desalinate  water from  the Persian Gulf  in amounts of  some  liters per day, which may then be industrially scaled up to actual application relevance for small villages at that sea.

Group picture of the HydroDeSal research network, taken in July 2023 during a general assembly in Mainz


Schematic of our approach for seawater desalination with thermo-sensitive and charged hydrogels


In  the  second  area  of  our  current  and prospective research, we aim to employ clustering of non-covalent junctions  in  supramolecular  polymer networks  to  serve  as  strong  reinforcement. This  effect makes  the networks as stable as covalently-jointed ones, but as their  crosslinking is still non-covalent, they can still be decomposed and thereby recycled. Our initial research focus is on networks in the melt and gel state, with a specific   view    to   conceptually   and   quantitatively   understand   the   interplay  of   supramolecular  and macromolecular  dynamics   in   further  interplay   with   junction  clustering, and  how  that  translates  into mechanical properties, specifically into mechanical spectra.


Cover pictures on the effect of junction spatial arrangement and clustering on transient polymer-network dynamics and mechanics


In  further  collaborative  research, our  group  is  a central  and leading part (spokespersonship) of two DFG-funded  coordinated  networks: the Research  Unit  FOR 2811 and  the  Collaborative  Research Center SFB 1552.  In  the  first,  we use  light  scattering, confocal microscopy, and rhology to unravel structure-property relations of amphiphilic polymer co-networks, with a special view on the interplay of structural inhomogeneity imparted  during  the process  of network conneciton and in momentary states of swelling. In the second, we use  similar   methods   to quantify  the effect  of   connectifity  defects  in  metallo-supramolecular  transient networks  with  model-type structure. Both these areas of research are central in their respective coordinated environments;  they  also deliver crucial knowledge to our application-oriented research on polymer-materials for a cyclic economy and for climate-change adaption.


Research Contacts


Recent Collaborations


R. von Klitzing, TU Darmstadt
Mechanics of Inhomogeneous Polymer Gels
ACS Macro Lett. 2015, 4, 698–703.
Macromol. Chem. Phys. 2023, 225, 2300389.

K. Saalwächter, Halle University
Structure and Defects in Sensitive Polymer Gels
Macromolecules 202255, 6573–6589.
Macromolecules 2022, 55, 5997–6014.
Soft Matter 2022, 18, 1071–1081.
Chem. Mater. 2023, 35, 4026–4037.

B. D. Olsen, Massachusetts Institute of Technology
Chain Dynamics in Supramolecular Polymer Gels
Macromolecules 2016, 49, 5599–5608.
Phys. Chem. Chem. Phys. 2022, 24, 4859–4870.


Recent and Current Industry Projects

Siemens AG
, Berlin, Germany
Polymer-Based Engine Insulators

Procter & Gamble Germany GmbH & Co Operations oHG, Schwalbach, Germany
Polyelectrolyte Superabsorbers

BASF SE, Ludwigshafen, Germany
Microgel Additives for Care Products