Jump to main content
Jump to site search
Access to RSC content Close the message box

Continue to access RSC content when you are not at your institution. Follow our step-by-step guide.


Issue 2, 2012
Previous Article Next Article

Predicting surface anchoring: molecular organization across a thin film of 5CB liquid crystal on silicon

Author affiliations

Abstract

Anchoring, i.e. the orientation and ordering of organic molecules at a surface and its persistence away from the interface, is a key phenomenon for liquid crystal (LC) physics and technology, as well as for organic transistors and photovoltaic cells where it strongly affects transport. Recent exciting experiments have started to explore anchoring at the nanoscale, but seemingly conflicting views are emerging, suggesting either a surface order very slowly decreasing with distance, or the expected exponential decay for adhesion energies. The current theoretical description of anchoring is, however, essentially empirical, and methods for predicting the molecular structuring and orientation are conspicuously lacking. Here we establish such predictive tools by using atomistic molecular dynamics simulations and obtain the order and molecular organization of 12 and 24 nm-thick nematic and isotropic films of the popular LC 4-n-pentyl-4-cyano biphenyl (5CB) at its interfaces with an atomically flat, H-terminated, (001) crystalline silicon surface and vacuum. We show that the film adopts a hybrid configuration, with a change of the 5CB preferred orientation from planar uniform at the silicon to perpendicular at the free surface. This variation is nearly discontinuous for the thin film, and continuous with twist and bend for the thicker one. Our findings provide for the first time a full description of the interfacial silicon-LC structure at the nanoscale level.

Graphical abstract: Predicting surface anchoring: molecular organization across a thin film of 5CB liquid crystal on silicon

Back to tab navigation

Supplementary files

Article information


Submitted
19 Sep 2011
Accepted
25 Oct 2011
First published
25 Oct 2011

Chem. Sci., 2012,3, 573-579
Article type
Edge Article

Predicting surface anchoring: molecular organization across a thin film of 5CB liquid crystal on silicon

A. Pizzirusso, R. Berardi, L. Muccioli, M. Ricci and C. Zannoni, Chem. Sci., 2012, 3, 573
DOI: 10.1039/C1SC00696G

Social activity

Search articles by author

Spotlight

Advertisements