Liquid crystal reactive monomer and liquid crystal panel

Referring now to FIG. 1 , a liquid crystal panel of the present invention is illustrated. The liquid crystal panel comprises:

a first transparent substrate 101 having a first alignment film 201 ; a second transparent substrate 102 having a second alignment film 202 ; and a liquid crystal composition filled between the first transparent substrate 101 and the second transparent substrate 102 , wherein the liquid crystal composition is in contact with the first and second alignment film, wherein the liquid crystal composition contains liquid crystal molecules 301 and at least one liquid crystal RM 302 represented by the formula (III), (IV) or (V).

Wherein,

X is selected from H or F;

p and q are the number of X group, the p and q are independently selected from an integer greater than or equal to 0 (such as 0, 1, 2 . . . ), and p+q≧1;

w and z are independently selected from an integer greater than or equal to 0 (such as 0, 1, 2 . . . ), and w+z≧1.

Wherein,

X is selected from H or F;

p, q and r are the number of X group, the p, q and r are independently selected from an integer greater than or equal to 0 (such as 0, 1, 2 . . . ), and r+p+q≧1;

w and z are independently selected from an integer greater than or equal to 0 (such as 0, 1, 2 . . . ), and w+z≧1.

Wherein,

w and z are independently selected from an integer greater than or equal to 0 (such as 0, 1, 2 . . . ), and w+z≧1.

The liquid crystal composition is a liquid crystal composition of one-drop filling technology. The transparent substrate is a glass substrate. The transparent substrate is a flexible polymer substrate or an inflexible polymer substrate.

A liquid crystal RM is provided in this embodiment, wherein the formula thereof is

and the scheme thereof is as follows.

The preparation method thereof is as follows:

(A) Preparing the Intermediate (1)

Dissolving 10 mmol 2,6-Dihydroxyanthraquinone in 150 ml Na 2 CO 3 solution at a concentration of 2N, followed by adding 127 mmol NaBH 4 into the reaction slowly. Stirring and carrying out reaction at room temperature for 3 hours, until no gas is produced. Then, heating and refluxing for 10 minutes. Acidizing the reaction by dripping concentrated HCl slowly into the reaction after cooling. The precipitate is dissolved with acetone after filtered out and collected. The solution is dehydrated with MgSO 4 , suction-filtrated, and then concentrated and vacuumed to obtain a red-brown solid. Lastly, the red-brown solid is purified with EA/Hexane=1/1 through silica gel column chromatography and recrystallized with ethanol to gain a light red-brown crystal;

(B) Preparing the Target Product

4.14 mmol intermediate (1) is loaded into a 250 ml two-neck bottle which is then deaerated by a vacuum dehydrating and deaerating device and filled with nitrogen for three times. The nitrogen is connected to the drip tube for making the reaction system anaerobic and anhydrous. At room temperature, 8.28 mmol triethylamine (Et 3 N) and 50 ml dehydrated tetrahydrofuran (THF) are added to the reaction system and are stirred until being dissolved. Finally, under an ice bath, 9.11 mmol methacryloyl chloride is added to react at the room temperature until the next day. The reaction system is suction-filtrated with THF, and the filtrate is collected, decompressed and concentrated, extracted with ethylamine (EA) and water, dehydrated with MgSO 4 and suction-filtrated, and then concentrated and vacuumed to obtain a yellow solid. Lastly, the yellow solid is purified with EA/Hexane=1/6 through silica gel column chromatography to gain a light yellow solid (which may be recrystallized with THF/methanol).

A liquid crystal RM is provided in this embodiment, wherein the formula thereof is

and the scheme thereof is as follows.

The preparation method thereof is as follows:

(A) Preparing the Intermediate (3)

Dissolving 10 mmol intermediate (1) in 150 ml KOH/THF solution at a concentration of 2N followed by adding 5 mmol 2-bromoethanol into the reaction slowly. Then, heating and refluxing for 24 hours. Acidizing the reaction by dripping concentrated HCl slowly into the reaction after cooling. The reaction system is extracted with ethylamine (EA) and water, dehydrated with MgSO 4 and suction-filtrated, and then concentrated and vacuumed to obtain a yellow liquid. Lastly, the yellow liquid is purified with EA/Hexane= 1/1 through silica gel column chromatography and recrystallized with ethanol to gain a light yellow liquid.

(B) Preparing the Target Product

10 mmol intermediate (3) is loaded into a 250 ml two-neck bottle which is then deaerated by a vacuum dehydrating and deaerating device and filled with nitrogen for three times. The nitrogen is connected to the drip tube for making the reaction system anaerobic and anhydrous. At room temperature, 8.28 mmol Et 3 N and 50 ml dehydrated THF are added to the reaction system and are stirred until being dissolved. Finally, under an ice bath, 9.11 mmol methacryloyl chloride is added to react at the room temperature until the next day. The reaction system is suction filtrated with THF, and the filtrate is collected, decompressed and concentrated, extracted with ethylamine (EA) and water, dehydrated with MgSO 4 and suction-filtrated, and then concentrated and vacuumed to obtain a yellow solid. Lastly, the yellow solid is purified with EA/Hexane=⅙ through silica gel column chromatography to gain a light yellow solid (which may be recrystallized with THF/methanol).

The embodiment provides a liquid crystal RM, which has a hard core and is contained in a liquid crystal composition, wherein the liquid crystal reactive monomer is represented by the formula (I):

Wherein,

A is the hard core, which is a group containing two or more benzene rings;

B 1 is a linkage group, which has a straight chain of at least one carbon atom;

R 1 and R 2 are polymer groups, and the R 1 and R 2 are the same or different groups;

X is selected from one of H, F, Cl, CF 3 and a straight-chain or branched-chain alkyl group;

n is the number of X group, and n≧1; and

the molecular weight of the liquid crystal reactive monomer is greater than or equal to 300.

Preferably, the liquid crystal RM also contains a linkage group B 2 between the hard core A and the polymer groups R 2 in a straight chain thereof, which is represented by the formula (II):

Wherein B 2 is a linkage group as well as B 1 , and the B 1 and B 2 each has a straight chain of at least one carbon atom; said B 1 and B 2 are the same or different groups.

Preferably, the polymer groups are selected from acrylate group or methacrylate group.

In this embodiment, the liquid crystal composition is a liquid crystal composition of one-drop filling (ODF) technology. The polyimide surface of the alignment film is formed on a transparent substrate. The transparent substrate is a glass substrate. The transparent substrate may also be a flexible polymer substrate or an inflexible polymer substrate.

In this embodiment, linkage groups having carbon chains of different lengths are introduced in the hard core containing 1˜3 benzene rings to examine the curing speed, the solubility in liquid crystal matrix and image sticking phenomenon of different liquid crystal RMs (RM B-1˜3 and RM C-1˜3) under the same polyimide surface of the alignment film condition. Specifically, each hard core of RM B-1˜3 contains 2 benzene rings and each hard core of RM C-1˜3 contains 3 benzene rings.

The liquid crystal RM B-1 matches the formula (I), in which the linkage group B 1 is a straight-chain alkyl group containing one carbon atom.

The liquid crystal RM B-2 matches the formula (I), in which the linkage group B 1 is a straight-chain alkyl group containing two carbon atoms.

The liquid crystal RM B-3 matches the formula (II), in which the linkage group B 1 is a straight-chain alkyl group containing two carbon atoms and the linkage group B 2 is a straight-chain alkyl group containing two carbon atoms.

The liquid crystal RM C-1 matches the formula (I), in which the linkage group B 1 is a straight-chain alkyl group containing two carbon atoms.

The liquid crystal RM C-2 matches the formula (I), in which the linkage group B 1 is a straight-chain alkyl group containing four carbon atoms.

The liquid crystal RM C-3 matches the formula (II), in which the linkage group B 1 is a straight-chain alkyl group containing two carbon atoms and the linkage group B 2 is a straight-chain alkyl group containing two carbon atoms.

The liquid crystal RM A, RM B and RM C are control groups, all of which contains no linkage group and the hard core independently contains 1˜3 benzene rings.

Referring now to Tab.2, the results of the examination of the curing speed, solubility in liquid crystal matrix and image sticking phenomenon of liquid crystal

RMs mentioned above under the same polyimide of the alignment film condition.

Clearly, it is come to the following conclusion:

(1) the more benzene rings the hard core contains, the better improvement of image sticking phenomenon is. Comparing to three groups: RM A, RM B and RM C; RM B-2 and RM C-1; and, RM B-3 and RM C-3, the number of the benzene ring contained in hard core is the only variable, it is clear that the more benzene rings the hard core contains, the better the improvement of image sticking phenomenon is and the higher the curing speed is.

(2) the longer the main chain of the liquid crystal RM is, the better the solubility in liquid crystal matrix is.

Comparing RM B and RM B-1˜3, RM C and RM C-1˜3, it is come to a conclusion that under the same number of the benzene ring contained in the hard core (i.e. the same volume of hard core), a longer main chain of the liquid crystal RM results in a better solubility of the liquid crystal RM in liquid crystal matrix. The improvement is more obvious in particularly excessive volume of hard core.

Therefore, the liquid crystal RMs of the present invention improve the solubility of the liquid crystal RMs in liquid crystal matrix by increasing the linkage groups to increase the length of the main chain of the liquid crystal RMs, so as to overcome the contradiction between the improvement of image sticking phenomenon and the solubility which exist in the conventional technologies.

The liquid crystal RMs of the present invention (liquid crystal RM B-1˜3 and liquid crystal RM C-1˜3) overcome the problems of the conventional liquid crystal RMs. The liquid crystal RMs of the present invention significantly improve the solubility of the liquid crystal RMs in liquid crystal matrix, and simultaneously solve the image sticking issue, raise the curing speed of the curing reaction between the liquid crystal RMs and the polyimide surface, and shorten the curing time, so as to achieve the purpose of energy saving and carbon reduction.

The present invention has been described with relative embodiments which are examples of the present invention only. It should be noted that the embodiments disclosed are not the limit of the scope of the present invention. Conversely, modifications to the scope and the spirit of the claims, as well as the equal of the claims, are within the scope of the present invention.