Polymer Used For Orientation Film Material and Method For Preparing Orientation Film

Abstract

The disclosure provides a polymer used for orientation film material and a method for preparing an orientation film. The polymer is formed by siloxane connecting with polyimide. The pre-tilt angle of liquid crystal molecules can be controlled within a wide range by controlling the content of siloxane in polymer, and the polymer has great heat resistance and mechanical properties. The method for preparing an orientation film of the disclosure comprises forming a precursor of orientation film by dissolving siloxane and precursor of polyimide (diamine monomer, dianhydride monomer) in a solvent, coating the precursor of orientation film on a substrate, and obtaining the orientation film after pre-solidifying and main-solidifying, the steps are simple and the prepared orientation film has a wide range of pre-tilt angle, such that the pre-tilt angle of liquid crystal molecules in the liquid crystal panels of the orientation film can be controlled within a wide range.

Claims

1. A polymer used for orientation film material, comprising: a polyimide chain; and a siloxane, connected with the polyimide chain as a side chain, wherein the siloxane has a connective group R and a functional group R, the connective group R is configured for connecting with the polyimide, and the functional group R is configured for controlling a pre-tilt angle of liquid crystal molecules so as to achieve orientating.

2. The polymer used for orientation film material according to claim 1, wherein the siloxane and the polyimide are connected by one of the following methods: (I) the connective group R in the siloxane connects with the polyimide, such that the other portion besides the connective group R in the siloxane pends on a lateral side of the polyimide as a branched chain; (II) the connective group R in the siloxane connects with the polyimide, such that the whole siloxane pends on a lateral side of the polyimide as a branched chain.

3. The polymer used for orientation film material according to claim 1, wherein the polyimide chain is ##STR00015## and wherein n and m are integers greater than 0.

4. The polymer used for orientation film material according to claim 1, wherein the siloxane is a branched siloxane, the formula of the branched siloxane is R.sub.1Si.sub.nO.sub.n1R.sub.2n+1, wherein n=4 or 13, R is (CO)OH, (CO)NH.sub.2, OH, or ##STR00016## R is a C3-10 linear alkyl or a branched alkyl, a C3-10 linear alkyl or a branched alkyl in which a CH.sub.2 is substituted by CHCH, CC, phenyl, cycloalkyl, or a phenyl; wherein the diameter of the branched siloxane is 1-3 nm.

5. The polymer used for orientation film material according to claim 1, wherein the siloxane is a caged oligomeric silsesquioxane, the formula of the caged oligomeric silsesquioxane is R.sub.1Si.sub.nO.sub.1.5nR.sub.n1, wherein n=6, 8, 10, or 12, R is (CO)OH, (CO)NH.sub.2, OH, or ##STR00017## R is a C3-10 linear alkyl or a branched alkyl, a C3-10 linear alkyl or a branched alkyl in which a CH.sub.2 is substituted by CHCH, CC, phenyl, cycloalkyl, or a phenyl; wherein the diameter of the caged oligomeric silsesquioxane is 1-3 nm.

6. The polymer used for orientation film material according to claim 1, wherein the mass percentage of the siloxane in the polymer is 150 wt %.

7. A method for preparing an orientation film, comprising: step 1, measuring siloxane, dianhydride monomer and diamine monomer in a mole ratio of 150:100:5099; step 2, providing an appropriate amount of a solvent, dissolving the measured dianhydride monomer, siloxane and diamine monomer in step 1 in the solvent, and obtaining a precursor of orientation film; step 3, providing a substrate, coating the precursor of orientation film prepared in step 2 on the surface of the substrate; step 4, pre-solidifying the precursor of orientation film disposed on the substrate, the temperature of pre-solidifying is 100130 C., and the time of pre-solidifying is 110 min; step 5, main-solidifying the precursor of orientation film disposed on the substrate, the temperature of main-solidifying is 210240 C., the time of main-solidifying is 2040 min, and obtaining an orientation film.

8. The method for preparing an orientation film according to claim 7, wherein in step 1, the siloxane is a branched siloxane or a caged oligomeric silsesquioxane.

9. The method for preparing an orientation film according to claim 7, wherein in step 2, the solvent is N-methylpyrrolidone, N-ethylpyrrolidine, butylrolcatone, or the combination thereof.

10. The method for preparing an orientation film according to claim 7, wherein the precursor of orientation film prepared in step 2 comprises siloxane, dianhydride monomer, diamine monomer and a solvent, wherein the mole ratio of the siloxane n1, the dianhydride monomer n2 and the diamine monomer n3 is 150:100:5099, and n2=n1+n3; the mass percentage of the siloxane in the precursor of orientation film is 0.010.5 wt %.

11. A method for preparing an orientation film, comprising: step 1, measuring siloxane, dianhydride monomer and diamine monomer in a mole ratio of 150:100:5099; step 2, providing an appropriate amount of a solvent, dissolving the measured dianhydride monomer, siloxane and diamine monomer in step 1 in the solvent, and obtaining a precursor of orientation film; step 3, providing a substrate, coating the precursor of orientation film prepared in step 2 on the surface of the substrate; step 4, pre-solidifying the precursor of orientation film disposed on the substrate, the temperature of pre-solidifying is 100130 C., and the time of pre-solidifying is 110 min; step 5, main-solidifying the precursor of orientation film disposed on the substrate, the temperature of main-solidifying is 210240 C., the time of main-solidifying is 2040 min, and obtaining an orientation film; wherein in step 1, the siloxane is a branched siloxane or a caged oligomeric silsesquioxane; wherein in step 2, the solvent is N-methylpyrrolidone, N-ethylpyrrolidine, butylrolcatone, or the combination thereof; wherein the precursor of orientation film prepared in step 2 comprises siloxane, dianhydride monomer, diamine monomer and a solvent, wherein the mole ratio of the siloxane n1, the dianhydride monomer n2 and the diamine monomer n3 is 150:100:5099, and n2=n1+n3; and the mass percentage of the siloxane in the precursor of orientation film is 0.010.5 wt %.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the disclosure, the accompanying drawings for illustrating the technical solutions and the technical solutions of the disclosure are briefly described as below.

[0038] FIG. 1 is a schematic view of a molecular structure of a polymer used for orientation film material according to the disclosure; and

[0039] FIG. 2 is a flow chart of the method for preparing an orientation film according to the disclosure.

DETAILED DESCRIPTION

[0040] The following description with reference to the accompanying drawings is provided to clearly and completely explain the exemplary embodiments of the disclosure. It is apparent that the following embodiments are merely some embodiments of the disclosure rather than all embodiments of the disclosure. According to the embodiments in the disclosure, all the other embodiments attainable by those skilled in the art without creative endeavor belong to the protection scope of the disclosure.

[0041] First of all, the disclosure provides a polymer used for orientation film material, comprising a polyimide chain and a siloxane, connected with the polyimide chain as a side chain, wherein the siloxane has a connective group R and a functional group R, the connective group R is configured for connecting with the polyimide, and the functional group R is configured for controlling a pre-tilt angle of liquid crystal molecules so as to achieve orientating.

[0042] Specifically, the siloxane and the polyimide are connected by one of the following methods:

[0043] (I) the connective group R in the siloxane connects with the polyimide, such that the other portion besides the connective group R in the siloxane pends on a lateral side of the polyimide as a branched chain;

[0044] (II) the connective group R in the siloxane connects with the polyimide, such that the whole siloxane pends on a lateral side of the polyimide as a branched chain.

[0045] Specifically, the polyimide chain is

##STR00004##

and wherein n and m are integers greater than 0.

[0046] Specifically, the siloxane is a branched siloxane or a caged oligomeric silsesquioxane.

[0047] The formula of the branched siloxane is R.sub.1Si.sub.nO.sub.n1R.sub.2n+1, wherein n=4 or 13, R is (CO)OH, (CO)NH.sub.2, OH, or

##STR00005##

R is a C3-10 linear alkyl or a branched alkyl, a C3-10 linear alkyl or a branched alkyl in which a CH.sub.2 is substituted by CHCH, CC, phenyl, cycloalkyl, or a phenyl.

[0048] Specifically, the connective group R is configured for connecting with the polyimide, and the functional group R is configured for controlling a pre-tilt angle of liquid crystal molecules so as to achieve orientating.

[0049] When n in the formula R.sub.1Si.sub.nO.sub.n1R.sub.2n+1 of the branched siloxane is 4 and 13 respectively, the structural formulas of the branched siloxane are respectively shown as (A) and (B):

##STR00006##

[0050] Specifically, the diameter of the branched siloxane is 1-3 nm.

[0051] The formula of the caged oligomeric silsesquioxane is R.sub.1Si.sub.nO.sub.1.5nR.sub.n1, wherein n=6, 8, 10, or 12, R is (CO)OH, (CO)NH.sub.2, OH, or

##STR00007##

R is a C3-10 linear alkyl or a branched alkyl, a C3-10 linear alkyl or a branched alkyl in which a CH.sub.2 is substituted by CHCH, phenyl, cycloalkyl, or a phenyl.

[0052] Specifically, the connective group R is configured for connecting with the polyimide, and the functional group R is configured for controlling a pre-tilt angle of liquid crystal molecules so as to achieve orientating.

[0053] Specifically, the diameter of the caged oligomeric silsesquioxane is 1-3 nm.

[0054] When n in the formula R.sub.1Si.sub.nO.sub.1.5nR.sub.n1 of the caged oligomeric silsesquioxane is 6, 8, 10 and 12 respectively, the structural formulas of the branched siloxane are respectively shown as (E), (F), (G) and (H):

##STR00008##

[0055] FIG. 1 is a schematic view of a molecular structure of a polymer used for orientation film material according to the disclosure, as shown in FIG. 1, the polymer comprises a polyimide chain and a branched siloxane connected with the polyimide as a side chain, the structure of the branched siloxane is shown as formula (A), the branched siloxane connects with the polyimide by R, such that the whole siloxane pends on a lateral side of the polyimide as a branched chain.

[0056] Preferably, the mass percentage of the siloxane in the polymer is 150 wt %.

[0057] Specifically, the mechanism of generating pre-tilt angle on the surface of the orientation film is:

[0058] (1) explanation of orientation in the view of energy: the mechanism of siloxane in the orientation film is similar to friction orientation, which generates a directional angle at the surface of the orientation film, such that the major axis of the liquid crystal molecules and the direction of R in the siloxane are identical so as to achieve a stable state, which has the lowest energy, and the liquid crystal molecules arrange along a certain direction, and the lowering level of energy relates to the content of the branched siloxane in the orientation film, when the content of siloxane is greater, the surface energy of the orientation film decreases more, such that the pre-tilt angle of the liquid crystal molecules can be controlled.

[0059] (2) explanation of orientation in the view of surface molecular chains: the liquid crystal molecules of the siloxane form the pre-tilt angle by steric effect of R in the orientation film, and the result of orientating would be affected by the content of siloxane, i.e., the quantity of R.

[0060] According to the polymer used for orientation film material of the disclosure, the polymer comprises a polyimide chain and a siloxane connected with the polyimide as a side chain, the siloxane has a connective group R configured for connecting with the polyimide and a functional group R configured for controlling a pre-tilt angle of liquid crystal molecules, specifically, the pre-tilt angle of liquid crystal molecules can be controlled between 0 and 90 by controlling the content of siloxane in polymer, such that the orientation film has a greater range of pre-tilt angle, and the pre-tilt angle of liquid crystal molecules can be controlled within a wide range; meanwhile, the polymer has great heat resistance and mechanical properties.

[0061] Referring to FIG. 2, the disclosure further provides a method for preparing an orientation film, comprising the following steps:

[0062] Step 1, measuring siloxane, dianhydride monomer and diamine monomer in a mole ratio of 150:100:5099.

[0063] Specifically, the siloxane is a branched siloxane or a caged oligomeric silsesquioxane.

[0064] The structures of the branched siloxane and the caged oligomeric silsesquioxane are described above, such that they are not described again.

[0065] Specifically, the structural formula of the dianhydride monomer can be:

##STR00009##

[0066] Specifically, the structural formula of the diamine monomer can be:

##STR00010##

[0067] Step 2, providing an appropriate amount of a solvent, dissolving the measured dianhydride monomer, siloxane and diamine monomer in step 1 in the solvent, and obtaining a precursor of orientation film.

[0068] Specifically, the solvent is N-methylpyrrolidone, N-ethylpyrrolidine, butylrolcatone, or the combination thereof.

[0069] The precursor of orientation film prepared in step 2 comprises siloxane, dianhydride monomer, diamine monomer and a solvent, wherein the mole ratio of the siloxane n1, the dianhydride monomer n2 and the diamine monomer n3 is 150:100:5099, and n2=n1+n3.

[0070] Preferably, the mass percentage of the siloxane in the precursor of orientation film is 0.010.5 wt %.

[0071] Step 3, providing a substrate, coating the precursor of orientation film prepared in step 2 on the surface of the substrate.

[0072] Step 4, pre-solidifying the precursor of orientation film disposed on the substrate, the temperature of pre-solidifying is 100130 C., and the time of pre-solidifying is 110 min.

[0073] Step 5, main-solidifying the precursor of orientation film disposed on the substrate, the temperature of main-solidifying is 210240 C., the time of main-solidifying is 2040 min, and obtaining an orientation film.

[0074] The disclosure provides a method for preparing an orientation film comprises forming a precursor of orientation film by dissolving siloxane and precursor of polyimide (diamine monomer, dianhydride monomer) in a solvent, coating the precursor of orientation film on a substrate, and obtaining the orientation film after pre-solidifying and main-solidifying, the steps are simple and the prepared orientation film has a wide range of pre-tilt angle, such that the pre-tilt angle of liquid crystal molecules in the liquid crystal panels of the orientation film can be controlled within a wide range.

[0075] Preferred embodiment 1 of the method for preparing an orientation film of the disclosure:

[0076] Step 1, measuring siloxane (b), dianhydride monomer (a) and diamine monomer (c) in a mole ratio of m:n:(nm)=150:100:5099.

[0077] Step 2, incorporating siloxane (b), dianhydride monomer (a) and diamine monomer (c) in a mixture of solvent constituted of N-methylpyrrolidone, N-ethylpyrrolidine, butylrolcatone and the combination. After dissolving, a precursor of orientation film is obtained.

[0078] Step 3, providing a substrate, coating the precursor of orientation film prepared in step 2 on the surface of the substrate.

[0079] Step 4, pre-solidifying the precursor of orientation film disposed on the substrate, the temperature of pre-solidifying is 100130 C., and the time of pre-solidifying is 110 min.

[0080] Step 5, main-solidifying the precursor of orientation film disposed on the substrate, the temperature of main-solidifying is 210240 C., the time of main-solidifying is 2040 min, and obtaining an orientation film.

[0081] Specifically, in steps 4 and 5, chemical reaction of the precursor of orientation film disposed on the substrate during the processes of pre-solidifying and main-solidifying are shown as below:

##STR00011##

[0082] An orientation film is prepared in step 5, the material of the orientation film is a polymer, the structural formula of the polymer is

##STR00012##

wherein m=205--, n=20500, and n>m.

[0083] According to the structural formula of the polymer, the branched siloxane (b) connects with the polyimide by its connective group

##STR00013##

such that the other portion besides the connective group

##STR00014##

in the siloxane pends on a lateral side of the polyimide as a branched chain.

[0084] According to the above description, the disclosure provides a polymer used for orientation film material and a method for preparing an orientation film. The polymer is formed by siloxane connecting with polyimide. The pre-tilt angle of liquid crystal molecules can be controlled within a wide range by controlling the content of siloxane in polymer, and the polymer has great heat resistance and mechanical properties. The method for preparing an orientation film of the disclosure comprises forming a precursor of orientation film by dissolving siloxane and precursor of polyimide (diamine monomer, dianhydride monomer) in a solvent, coating the precursor of orientation film on a substrate, and obtaining the orientation film after pre-solidifying and main-solidifying, the steps are simple and the prepared orientation film has a wide range of pre-tilt angle, such that the pre-tilt angle of liquid crystal molecules in the liquid crystal panels of the orientation film can be controlled within a wide range.

[0085] Note that the specifications relating to the above embodiments should be construed as exemplary rather than as limitative of the present disclosure. The equivalent variations and modifications on the structures or the process by reference to the specification and the drawings of the disclosure, or application to the other relevant technology fields directly or indirectly should be construed similarly as falling within the protection scope of the disclosure.