Video-Tutorials

Chemiefabrik der Zukunft

Biofilme haben als gefürchtete Krankenhauskeime schlechtes Image. Sie können aber auch von großem technologischen Nutzen sein. Ihr künftiges Potenzial als ressourcenschonender Elektrolyt in Brennstoffzellen oder für synthetisch produzierte Pharmaka wie Insulin. Solche Zukunfts-Anwendungen werden im Rahmen des bayerischen Forschungsverbundes BayBiotech untersucht. Susanne Päch hat sich zwei Wissenschaftler von der Uni Bayreuth zu einem Skype-Interview ins Studio geholt, um über neueste Forschungen auf diesem Gebiet zu sprechen. Andreas Greiner ist Professor für Polymerchemie und Inhaber des Lehrstuhls für makromolekulare Chemie, während der Biotechnologe Patrick Kaiser am Lehrstuhl für Bioprozesstechnik derzeit seine Promotion abschließt.

High strength in combination with high toughness in robust and sustainable polymeric materials

Xiaojian Liao, Martin Dulle, Juliana Martins de Souza e Silva, Ralf B. Wehrspohn, Seema Agarwal, Stephan Förster, Haoqing Hou, Paul Smith, Andreas Greiner Science, 2019, 1376-1379 DOI: 10.1126/science.aay9033

In materials science, there is an intrinsic conflict between high strength and high toughness, which can be resolved for different materials only through the use of innovative design principles. Advanced materials must be highly resistant to both deformation and fracture. We overcome this conflict in man-made polymer fibers and show multifibrillar polyacrylonitrile yarn with a toughness of 137 ± 21 joules per gram in combination with a tensile strength of 1236 ± 40 megapascals. The nearly perfect uniaxial orientation of the fibrils, annealing under tension in the presence of linking molecules, is essential for the yarn’s notable mechanical properties. This underlying principle can be used to create similar strong and tough fibers from other commodity polymers in the future and can be used in a variety of applications in areas such as biomedicine, satellite technology, textiles, aircrafts, and automobiles.

Ultralight, Soft Polymer Sponges by Self-Assembly of Short Electrospun Fibers in Colloidal Dispersions

Gaigai Duan , Shaohua Jiang , Valérie Jérôme , Joachim H. Wendorff , Amir Fathi , Jaqueline Uhm , Volker Altstädt , Markus Herling, Josef Breu , Ruth Freitag , Seema Agarwal , and Andreas Greiner,  Adv. Funct. Mater. 2015, 25, 2850–2856

Ultralight polymer sponges are prepared by freeze-drying of dispersions of short electrospun fi bers. In contrast to many other highly porous materials, these sponges show extremely low densities (<3 mg cm −3 ) in combination with low specifi c surface areas. The resulting hierarchical pore structure of the sponges gives basis for soft and reversibly compressible materials and to hydrophobic behavior in combination with excellent uptake for hydrophobic liquids. Owing to their large porosity, cell culturing is successful after hydrophilic modifi cation of the sponges.

Functionalization of gold nanoparticles in two-phase system -via ligand exchange-

The short video shows the well-established method of ligand-exchange, which is used for the introduction of ligands to nanoparticles in one-phase and two-phase systems. Here is shown ligand exchange of citric acid ligands on gold nanoparticles against vinyl-pyridine functionalized polystyrene.