Options
Imbibition in mesoporous silica: rheological concepts and experiments on water and a liquid crystal
Publikationstyp
Journal Article
Date Issued
2011-05-11
Author(s)
Volume
23
Issue
18
Start Page
184109
Article Number
184109
Citation
Journal of Physics Condensed Matter 23 (18): 184109 (2011-05-11)
Publisher DOI
Scopus ID
PubMed ID
21508488
Publisher
IOP Publ.
We present, along with some fundamental concepts regarding imbibition of liquids in porous hosts, an experimental, gravimetric study on the capillarity-driven invasion dynamics of water and of the rod-like liquid crystal octyloxycyanobiphenyl (8OCB) in networks of pores a few nanometers across in monolithic silica glass (Vycor). We observe, in agreement with theoretical predictions, square root of time invasion dynamics and a sticky velocity boundary condition for both liquids investigated. Temperature-dependent spontaneous imbibition experiments on 8OCB reveal the existence of a paranematic phase due to the molecular alignment induced by the pore walls even at temperatures well beyond the clearing point. The ever present velocity gradient in the pores is likely to further enhance this ordering phenomenon and prevent any layering in molecular stacks, eventually resulting in a suppression of the smectic phase in favor of the nematic phase.
DDC Class
530: Physik