DD240385A1 - APPLICATION OF FERROELECTRIC FLUID CRYSTALS - Google Patents

Abstract

The invention relates to ferroelectric liquid crystals, which are used as a medium for the production of fast switching displays with memory properties for the representation of numbers, characters and images. The aim of the invention are fast-switching displays with memory properties that contain chemically and thermally stable ferroelectric crystalline liquids. It has been found that crystalline-liquid derivatives of branched acyclic a-chlorocarboxylic acids of the general formula alone, in mixtures with one another and with other crystalline liquid or non-crystalline substances form ferroelectric crystalline liquid phases which are suitable for use in displays.

Description

R ¹ = (CH ₃ J ₂ CH-, (CHa) ₂ CH-CH ₂ -, C ₂ H ₅ -CH (CH ₃ ) -

R ² = -QH ₂ I _{+ 1} , -O-C ₁ H ₂ , + v-S-CiH ₂ , _{+ 1} , -OCO-CiH ₂ , ₊₁ , -COO-CiH ₂ , _{+ 1}

I = 1-12, are used alone, in mixtures with each other and with other crystalline liquid or non-crystalline liquid substances.

Field of application of the invention

The invention relates to ferroelectric liquid crystals, which are used as a medium for the production of fast switching displays with memory properties for the representation of numbers, characters and images.

Characteristic of the known technical solutions

It has already been proposed to use ferroelectric liquid crystals for the preparation of fast switching displays with memory properties (N.A. Clark, S. T. Lagerwall, Appl. Phys. Lett., 36, 899 [198O]).

Although a number of substances having ferromagnetic properties are already known, there are still no materials with optimum properties (ST Lagerwall, I. Dahl, Mol. Cryst. Liq. Cryst. [1984]; D. Demus, H. Zaschke, Liquid Crystals Tables II, VEB German publishing house for basic industry Leipzig 1984).

In some cases, the substances are chemically and thermally unstable or they have high melting temperatures or the spontaneous polarization is too small due to the low, directly connected to the chiral group Dipolmomentes.

Therefore, new substances are constantly being sought which are improved in their properties and which are suitable for the production of ferroelectric crystalline-liquid mixtures. ,

Object of the invention

The aim of the invention are fast-switching displays with memory properties that contain chemically and thermally stable ferroelectric crystalline liquid substances.

Explanation of the essence of the invention

The object of the invention are new ferroelectric liquid crystals that can be used in fast-switching displays with memory properties. , ,

It has been found that crystalline liquid derivatives of branched acyclic-chlorocarboxylic acid of the general formula

R ¹ -CH-C00- <T) - (X) _D -Cl

J_ (ij

η = 0.1; m = 0.1; ο = 0.1; ρ = 0.1 X = -COO-, -OOC-, -CH ₂ -CH ₂ -Y = X, -CH ₂ -, - N = N (O) -

5> -Ο

B) = c \ =

R ¹ = (CH ₃ J ₂ CH-, (CH ₂ ) ₂ CH-CH ₂₁ C ₂ H ₅ -CH (CH ₃ ) - '

R = C | H ₂ | ₊ 1, -0-C | H ₂ | + 1, -SC] H ₂ I ₊ i, -CO-CiH ₂ I ₊ i,

-OOC-CiH ₂ , + 1, -COO-C ₁ H ₂ I + 1, -NH-CiH ₂ I ₊ II = 1-12

mean, alone, in mixtures with each other and with other crystalline-liquid or non-crystalline liquid substances form ferroelectric crystalline liquid phases, which are suitable for use in displays.

The substances are colorless, chemically and thermally very stable and have a high dipole moment due to the Cl substituent directly at the chiral center and thus a high spontaneous polarization.

embodiment example 1

Tables 1-6 below show the transformation temperatures of substances according to the invention.

Where:

K = crystalline solid state SJ = ferroelectric smectic C phase Sa, S ₈ , S _G = smectic A, B, G phase CH = cholesteric phase Is = isotropic liquid phase

N = nematic phase,

Example 2

Mixtures were prepared from the following substances:

substance

T / ° C

K Sc * S _A CH Blue Is

N phase

¹ 'C ₈ H ₁₇ O - ^ - COO-

> -00 C-CH-CHC CH ₃₎ Cl

 153 - --188

-OOC-GH-CH (CH 2) Cl

• 66 (-45) · 68 · 70 -72

 38-39-44 -60 -62.5 - -

• 40 -51 -65 - -

^{5 C} 8 ^H 17 °

• 28.5 -.5.5.5 -62 -68 - -

^{6 C} 8 ^H 17 ° -

-COOHfO) -OC ₆ H ₁₃

 55 -66 - --89,5 - -

• 62.5 -73.5 - - 90.5 - -

The following mixtures were prepared from these substances:

1) mixture 1

The mixture consists of

No. 1 (S) - (+) - 11- [4-n-octyloxybenzoyloxy] -4 '- [2-chloro-3-methylbutyloxy] biphenyl No. 2 (S) (+) - 4-n-decyloxybenzoic acid -4 '- [2-chloro-3-methylbutyloxy] phenyl ester

2) Mixture 2

The mixture consists of

No. 1 (SX + liWn-octyloxybenzoyloxyl - ^ - ^ - chloro-S-methylbutyloxyl-biphenol No. 2 (SX + 1-n-decyloxybenzoic acid) ^ - ^ - chloro-S-methylbutyryloxy-phenyiester No. 3 (S) -4-octyloxy benzoic acid 4- [2-methylbutyloxy] phenyl ester

3) Mixture 3

The mixture consists of

No. 1 (S) (+) - 1- [4-n-octyloxybenzoyloxy] -4 '- [2-chloro-3-methylbutyryloxy] biphenyl No. 2 (S) (+) - 4-n-decyoxybenzoic acid 4- [2-chloro-3-methylbutyryloxy] -phenyl ester No. 5 5-n-octyl-2- [4-n-octyloxy-phenyl] -pyrimidine

4) mixture 4

The mixture consists of

No. 1 (S) (+) - 1- [4-n-octyloxybenzoyloxy] -4 '- [2-chloro-3-methylbutyryloxy] -biphenyl No. 2 (SX + 1-n-decyloxybenzoic acid) -' -chloro-S-methylbutyryloxy-J-phenylester No. 4 (S) -4-nn-decyloxybenzoic acid 4- [2-methylbutyloxy] -phenyl ester

25 mol% 75 mol%

16.1 mol%

48.2 mol% 35.7 mol%

23.75 mole%

71.25 mol%

5.00 mol%

13.5 mol% 25.3 mol% 61.2 mol%

5) 'mixture 5

The mixture consists of

No. 1 (S) (+) - 1 [-4-n-octyloxybenzoyloxy] -4 '- [2-chloro-3-methylbutyryloxy] biphenyl No. 2 (S) (+) - 4-n-decyloxy- benzoic acid 4- [2-chloro-3-methylbutyryloxy] -phenyl ester No. 4 (S) (+) - n-Decyloxy-benzoic acid 4- [2-methylbutyloxy] -phenyl ester No. 5 5-n-octyl-2 - [4-n-octyloxy-phenyl] -pyrimidine

6) Mixture 6

The mixture consists of

No. 1 (S) (+) - 1 - [- 4-n-octyloxybenzoyloxy] -4 '- [2-chloro-3-methylbutyryloxy] biphenyl No. 3 (S) -4-n-octyloxybenzoic acid 4- [2-methylbutyloxy] -phenyl ester No. 6 4-n-octyloxybenzoic acid 4-n-hexyloxyphenylester No. 7 4-n-octyloxybenzoic acid 4-n-octyloxyphenylester

7) mixture 7

the mix consists of

No. 2 (S) (+) - 4-n-Decyloxybenzoic acid 4- [2-chloro-3-methylbutyryloxy] -phenyl ester No. 3 (S) -4-n-octyloxybenzoic acid-4- [2-methylbutyloxy] - phenyl ester No. 6 4-n-octyloxybenzoic acid 4-n-hexyloxyphenyiester No. 7 4-n-octoxybenzoic acid 4-n-octyloxyphenyl ester

8) mixture 8

The mixture consists of

No. 1 (S) (+) - 1- [4-n-octyloxybenzoyloxy] -4 '- [2-chloro-3-methylbutyryloxy] biphenyl No. 2 (S) (+) - 4-n-decyloxybenzoic acid 4- [2-chloro-3-methylbutyryloxy] -phenyl ester No. 4 (S) -4-n-Decyloxybenzoic acid 4- [2-methylbutyloxy] -phenyl ester No. 6 4-n-Octyloxybenzoic acid 4-n-hexyloxyphenyiester No 7-4-n-octyloxybenzoic acid 4-n-octyloxyphenyl ester

These mixtures have the following transformation temperatures ( ⁰ C):

mixture

Umwandlungspunkte- sc Sat. -CH K • 63 • 86.5 • 92 • 23  45 • 75 • 89 • 18 • 58 • 85.5 • 90.5 • 24 • 52 • 77 • 82 • 21 • 39 • 70  76 • 15 • 55 • 66   79.5 • 17.5 , • 48 • 68 • 74 • 17 • 54 • 76 • 81.5 • 28

phase

, is

100 96.5

21.5 mol% 52 mol% 15 mol%

5 mol% 56 mol% 22.8 mol% 16.2 mol%

10 mol% 53 mol% 21.6 mol% 15.3 mol%

9.5 mol% 17.67 mol% 42.79 mol% 17.5 mol% 12.54 mol%

All mixtures have ferroelectric phases that are stable at room temperature or slightly higher temperatures.

Claims (1)

Invention claim: 1. Application of ferroelectric liquid crystals in displays', characterized in that crystalline liquid derivatives of branched acyclic a-chlorocarboxylic acids of the general formula η = 0.1; m = 0.1; ο = 0.1; ρ = 0.1
X = -COO-, -00C-, -CH ₂ -CH ₂ -Y = X, -CH ₂ -, - N = N -, - N = N (O) -