Anke's Promotion


Anke mit Hut

Hut Nahansicht

Anke Henschel proudly presents her mortarboard from her PhD graduation.


Spontaneous Imbibition - Surface Freezing - Monolayer Sticking

Ever heard of „surface freezing“ and its romantic background? This phenomenon,
which arguably constitutes one of the most simple molecular self-assembly processes in nature, refers to the spontaneous formation of a microscopically thin, crystalline layer floating on top of the melt close to, but above the freezing temperature of the bulk liquid. Capillary filling experiments on molten wax in tiny pores (only a few nanometers across), published today in Physical Review Letters, testify that this collective orientational molecular ordering is also observable at advancing, highly curved liquid menisci self-propelled by capillarity in silica pores. There you may call it “meniscus freezing” and it significantly affects the imbibition dynamics in the mesoporous matrix.

Optical Birefringence Study on Confined n-Hexane

Surprisingly, spatially nano-confined liquid n-hexane is still an isotropic liquid: We did not find any hints of collective orientational order as a function of filling of glass capillaries with 7 nm mean diameter and 400 micrometer length. A combined optical birefringence/vapour sorption isotherm study reporting this message was published in Physical Review B today. The absence of any orientational order in the confined liquid state highlights the importance of an anisotropic crystallization process named after Percy W. Bridgman (a Harvard scholar and Nobel Laureate) for the occurence of preferred orientations upon solidification of n-hexane and medium-length n-alkanes in nanochannels of mesoporous silicon.


Patrick wins the best talk award at the Nano- and Microfluidics workshop in Bad Honnef, Germany. He presented work of Simon Gruener on spontaneous imbibition dynamics of linear hydrocarbons (n-alkanes) in mesoporous silica. Congrats to both !