Smectic and nematic order of 8OCB

October 12, 2010

Optical birefringence study on the phase transition behavior of a rod-like liquid crystal (8OCB), confined in silica channels, published in Applied Physics Letters (pdf).

Thermotropic nematic order upon nano-capillary filling

5.4.2013 Thermotropic nematic order upon nano-capillary filling

Our study on the optical birefringence and light absorption of silica nanochannels filled by a rod-like liquid crystal (published in Physical Review E (pdf)) documents that the thermo-optical properties of nanoporous systems (or single nano-capillaries) can be tailored over a surprisingly wide range simply by variation of the the filling fraction with liquid crystals.

Three-stage disputation marathon


Patrick mastered a three-stage disputation marathon within one week - Matthias and Simon successfully finished their PhD!

from left to right: Matthias Wolff, René Berwanger, and Simon GruenerMatthias Wolff, René Berwanger, and Simon Gruener (f.l.t.r.) proudly present their mortarboards from their PhD graduation. Congratulations!

Theses and disputation talks are available online!

Neutron Spin Echo study on confined liquids

September/October 2010

Neutron spin echo studies on the dynamics of polymers and alkanes confined in silicon nanochannels (published in The Journal of Physical Chemistry Letters and in Macromolecules) indicate sticky boundary layers and anisotropic self-diffusion dynamics.

Polymorphism of Nano-Alcohol

Pure alcohol (ethanol) exhibits polymorphism: Depending on the cooling rate it solidifies in a crystalline, orientational glass or structural glass state. As we report in Philosophical Magazine Letters this polymorphism is conserved upon geometric nano-confinement in tiny channels, a few nanometers across. However, the critical cooling rates, necessary in order to achieve the glassy phases, are two orders of magnitude smaller than in the bulk state. A pdf-copy of the manuscript can be found here.

Phase diagram of ethanol (bulk).