Maria Morits was able to create the first bulk nanocomposite with globally aligned nanoplatelets (2D clay platelets 1nm thickness). These materials exhibit high strength (250MPa) and stiffness (25GPa), and display toughness, where fracture mechanics strictly depend on relative humidity. Interestingly, the material is tough in wet conditions due to plasticity and tough in dry state due to step wise fracture. We estimate the maximum modulus to 70GPa and strength of 500MPa provided more defined (synthetic) clays are used as compared to the natural ones.
After complexation of the brushes with complementarily charged block copolymers, the surface spontaneously changed its shape to adopt a screw-like morphology or helix. well-developed helices were monohelices which is untypical in spontaneous self-assembly processes. The Structures were analyzed with cryogenic electron tomography, one of the most advanced imaging techniques in nanoscience.
We utilized versatile thiol-ene click reactions to change the volume of one of the blocks as well as the interaction parameters. Among the morphologies we found double helices and triple helices.
01.08.2016 New Group Member - Tai-Lam Nghiem
The group welcomes M.Sc. Tai-Lam Nghiem.
He just started his PhD on "Complex block copolymer self-assemblies" with the aim to create stimuli-responsive superstructures, precise colloidal polymers, and interpolyelectrylyte complexes. Information about him can be found here and his personal page is here.
The poly(4-vinylpyridine) (P4VP) is able to accommodate various organic compounds through hydrogen-bonding. We utilized this feature to attach photoresponsive azobenzene moieties thereby changing the volume fraction of the P4VP phase and hence the morphology. We were able to create various Janus nanostructures from one single terpolymer including Janus cylinders, Janus sheets, and novel hexagonally-perforated Janus sheets.
We found that a large range of previously unknown nanostructure can not only be generated but also targeted with proper planning of the block composition. We thereby subdivided the four solution topologies known since the year 1995 (spheres, cylinders, sheest and vesicles) into four new sub-classes, including patchy cylinders, double helical cylinders, perforated sheets and striped and perforated vesicles.