A Reinvestigation of the Purported Induction of Preferred Conformations of Achiral Rigid Rod Solutes in Cholesteric Media

Abstract

Several achiral rigid rod solutes were dissolved in two different cholesteric liquid crystalline solvents, and pitch measurements were made by the Cano wedge, droplet and fingerprint methods. In the first two techniques, no effect of the achiral solutes on the pitch occursat low concentration. Although some regimes of the samples prepared by the fingerprint technique show pitch shortening in the presence of some of the achiral solutes, the overall conclusion is that, contrary to previous reports, there appears to be no convincing evidence for the induction of preferred conformations in achiral solutes.

Key Words:

• Cholesteric
• liquid crystal
• chirality
• pitch