Tilt angle measurement of low molar mass organosiloxane liquid crystals

In this paper we present a modified ‘rotating analyser’ technique that allows rapid and continuous in situ measurements of the optical tilt angle (θ). Using this technique we will detail the tilt angle behaviour in mono-mesogen (AB) and bi-mesogen (ABA) low molar mass orga- nosiloxanes. The AB type molecules exhibit only the ferroelectric SmC* phase and possess a high tilt angle (42-45°) that is independent of temperature throughout the phase range. The ABA molecules containing three silicon atoms exhibit antiferroelectric SmC*Aphases. The tilt angle behaviour during a field induced SmC*A- SmC* transition has also been investigated.