Ferroelectric, pyroelectric and electro-optic properties of a chiral side chain copolymer with high polarization and a broad C∗ phase

Helgee, Bertil; Hjertberg, Thomas; Skarp, Kent; Andersson, Gunnar; Gouda, F.

doi:10.1080/02678299508036705

Cited by 30 publications

(26 citation statements)

References 19 publications

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“…The basic mesogenic core of AC11 consisted of a phenyl biphenylcarboxylate unit [9] that is known to favor the SmC-SmA phase sequence. Two different architectures of organosiloxanes were derived from AC11 by a Pt-catalyzed hydrosilylation reaction [10]: a chiral mesogen was linked to one disiloxane segment in MSi2-AC11, or two chiral mesogens were linked at both ends of a trisiloxane segment in DSi3-AC11.…”

Section: Resultsmentioning

confidence: 99%

“…Butyl Ester [9] (AC11). 5.00 g (13.6 mmol) of 3, 3.25 g (13.6 mmol) of 5 and 0.26 g (1.8 mmol) of 4-pyrrolidinopyridine (PPy) were dissolved in 100 ml of dry dichloromethane and the solution cooled to 0 • C. 2.80 g (13.6 mmol) of dicyclohexylcarbodiimide (DCC) in 5 ml of dry dichloromethane was then added dropwise.…”

Section: (R)-2-{[4 -(10-undecenyl-1-oxy)-biphenyl-4-carbonyloxy)phenomentioning

confidence: 99%

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Structure and Properties of New de Vries SmA* Liquid Crystals

Reihmann¹,

Crudeli²,

Blanc³

et al. 2004

Ferroelectrics

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International audienceWe synthesized a chiral mesogen AC11 and two different siloxanes MSi2-AC11 and DSi3-AC11 derived from it by a hydrosilylation reaction. The effects of varying the molecular architecture were investigated with special attention being devoted to the occurrence of the de Vries SmA* phase. Strong hints that all the three molecules follow the scenario suggested by de Vries were found in the behavior of the susceptibility by studies of their electrooptical response in the SmA* phase. In particular, DSi3-AC11 containing two mesogens interconnected by a siloxane spacer presented a critical exponent γ as high as 1.97, indicating a practically pure de Vries behavior. Temperature-dependent X-ray analysis revealed that the three materials underwent a small layer shrinkage at the SmA*–SmC* transition

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Section: Resultsmentioning

confidence: 99%

Section: (R)-2-{[4 -(10-undecenyl-1-oxy)-biphenyl-4-carbonyloxy)phenomentioning

confidence: 99%

Structure and Properties of New de Vries SmA* Liquid Crystals

Reihmann¹,

Crudeli²,

Blanc³

et al. 2004

Ferroelectrics

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“…The details of the synthetic route and ferroelectric properties of this FLCP material are reported elsewhere. 7 The value of its bulk spontaneous polarization at room temperature is 160 nC/ cm 2 . It exhibits the SmC * -SmA * phase transition at 105°C which, as we shall see later, is the same for the thin FLCP layer.…”

Section: Methodsmentioning

confidence: 99%

Ferroelectric switching of electrically commanded alignment layers for liquid crystal displays

Drevenšek‐Olenik

Kunstelj

Koncilija

et al. 2006

Journal of Applied Physics

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Optical second harmonic generation (SHG) was used to probe the structural and dynamic properties of electrically commanded alignment layers for liquid crystal displays. The layers were 200nm thick and were made of siloxane-based side chain ferroelectric liquid crystal polymer (FLCP). The effect of an external dc electric field in the range of 0–2V∕μm on the SHG signal was probed in an empty sandwich cell and in a cell filled with an isotropic liquid (hexadecane). In both cases the nonlinear induced polarization shows characteristics of the “V-shaped” switching, which is associated with a relatively minor reorientational perturbation of the film. This signifies a presence of domain structure, which is strongly pinned to the substrates. The values of switching times deduced from the SHG response are two orders of magnitude larger from the values obtained by optical birefringence measurements. This observation suggests that in the top surface layer of the FLCP, which is mainly responsible for the birefringence and also for the so-called electrically commanded surface effect, the reorientation of the polymer side chains takes place much faster than in the regions close to the substrate.

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“…di(4PPB11)3Si (5e). The precursor for this dimer has the longest spacer employed in this study and has previously been used to make side chain LC polysiloxanes [33]. It has several similarities to the side chain siloxane polymer with the same monomer unit.…”

Section: Di(4ppb5)3si (5c)mentioning

confidence: 99%

“…4PPB11 (3e). The monomer with 11 carbons in the spacer has been studied previously [33]. It has a fairly wide SmC* phase at 30-74uC topped by an SmA* phase at 74 -106uC.…”

Section: Antiferroelectric Siloxane Dimers 1143mentioning

confidence: 99%

A new series of siloxane liquid crystalline dimers exhibiting the antiferroelectric phase

et al. 2005

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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 SmC A phase, which in several cases has a large tilt angle greater than 40u 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.

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Ferroelectric, pyroelectric and electro-optic properties of a chiral side chain copolymer with high polarization and a broad C∗ phase

Cited by 30 publications

References 19 publications

Structure and Properties of New de Vries SmA* Liquid Crystals

Structure and Properties of New de Vries SmA* Liquid Crystals

Ferroelectric switching of electrically commanded alignment layers for liquid crystal displays

A new series of siloxane liquid crystalline dimers exhibiting the antiferroelectric phase

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