A new series of siloxane liquid crystalline dimers exhibiting the antiferroelectric phase
Artikel i vetenskaplig tidskrift, 2005

In this paper, we report the study of a new series of symmetric chiral liquid crystalline siloxane dimers, their related monomers, and two of those monomers with heptamethyltrisiloxane attached. All the dimers coupled with a trisiloxane show the SmCA phase, which in several cases has a large tilt angle greater than 40° over a wide temperature range, as well as high spontaneous polarisation in the field-induced ferroelectric state. Spacer lengths of 3-6 and 11 carbons between the siloxane central unit and the mesogenic cores were used. Monomers with 3-6 carbons in the spacer showed only orthogonal phases while the monomer with an 11-carbon spacer, as well as the monomers with siloxane attached, have a high tilt angle ferroelectric phase. The materials were characterized by means of DSC, NMR, X-ray diffraction, electro-optical methods (tilt angle and texture characterization) and polarization measurements.

ferroelectric

liquid crystals

antiferroelectric

dimers

tilt angle

siloxane

Författare

Nils Olsson

Göteborgs universitet

Bertil Helgee

Chalmers, Kemi- och bioteknik, Polymerteknologi

Göteborgs universitet

Gunnar Andersson

Göteborgs universitet

Lachezar Komitov

Göteborgs universitet

Liquid Crystals

0267-8292 (ISSN) 1366-5855 (eISSN)

Vol. 32 1139-1150

Ämneskategorier

Polymerkemi

Atom- och molekylfysik och optik

Organisk kemi

DOI

10.1080/02678290500268176