The Group

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December 2016
December 2016

We are fascinated by macromolecules with unprecedented structures and dimensionalities. Making such structures not only requires advancing polymer synthesis into molar mass regimes previously inaccessible, but also designing the monomers such that the macromolecules synthesized from them automatically adopt a particular shape. While these two aspects all by themselves can already be challenging, an important goal is to do all this maintaining as far as possible the atomistic integrity of the products created. Even in a macromolecule whose molar mass is e.g. 100 or 1000 MDa, we still want to know how the exact atom connectivity is in every volume element of the structure.

More concretely, we make cylindrically shaped macromolecules, whose dimensions can easily compete with viruses and whose hardness rivals that of any non-cross-linked polymeric colloidal particle. And we make covalently connected monolayer sheets with an internal periodicity, the lateral extension of which can easily exceed 100 micrometers. For such macromolecules we have coined the term 2D polymer. We also have several other projects.

The desire for knowing the connectivity in huge molecular objects is not driven by an ‘art for art’s sake’ attitude, but by the conviction that properties of polymeric materials can eventually be traced back through several hierarchy levels all the way to the molecular, the atomistic level. Often it is the defects created during synthesis that control properties of materials and their avoidance is thus crucial to decipher the intrinsic attributes of a particular macromolecule and the material obtained from it.

Dealing with huge molecular entities has two important consequences. More often than not we find that analytical methods cannot be properly applied anymore just because of the outrageously high number of atoms contained in each individual macromolecule. Sensitivity turns critical. Moreover we increasingly find ourselves in a situation where the commonly applied models of polymer physics cannot reasonably be applied anymore. Thus there is an issue with ‘understanding’ the own molecules. These two aspects explain why being located in a materials department is so essential for us. We need advice and support by top notch specialists that can help us pushing the limits of analytical methods. We also need advice by theoreticians who can help us develop new concepts for our cylinders and sheets. Of course we get this support also from the outside. But being part of a local network helps advancing much faster; also it adds to the daily fun.

Now, what do we really do? We spend a long time on understanding a particular bond formation reaction and how it can be optimized such that it operates with highest fidelity. We then implement this reaction as the key element in the process that furnishes the targeted macromolecule. Measures of pre-ordering or pre-orienting of monomer molecules often assist this process. Thereafter isolation, handling, and analyzing of the product sometimes keep us busy for years. This all is woven into a continuous exchange with internal and external colleagues.

Having understood the key reaction beforehand—and thus the organic chemistry behind all this—is important for two reasons. Firstly, one does not have to start from completely unknown territory when it comes to analyzing the product. There is at least a substantiated expectation to begin with. Secondly, if the product polymer has attractive properties one can immediately assess whether a large scale access is within reach.

We are intrigued by what synthesis offers in terms of creation of novel materials and are passionate about the opportunities that complex macromolecules offer in terms of cooperation.

 
 
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30.03.2017
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