阅读说明：本技术 长楔形侧链液晶聚合物及亚十纳米结构光诱导取向方法 (Long wedge-shaped side chain liquid crystal polymer and sub-ten nano structure light-induced orientation method ) 是由 陈尔强 蒋旭强 杨爽 于 2020-05-09 设计创作，主要内容包括：长楔形侧链液晶聚合物及亚十纳米结构光诱导取向方法,本发明涉及一种长楔形侧链液晶聚合物及其多链超分子柱状结构的光诱导取向方法,通过选择合适的光响应棒状基元A或B,使聚合物形成的亚十纳米柱状结构具备光诱导取向能力,实现光诱导的亚十纳米表面图案化。(The invention discloses a long wedge-shaped side chain liquid crystal polymer and a light-induced orientation method of a sub-ten nano structure, and relates to a long wedge-shaped side chain liquid crystal polymer and a light-induced orientation method of a multi-chain supermolecular columnar structure of the long wedge-shaped side chain liquid crystal polymer.)

1. The long wedge-shaped side chain liquid crystal polymer is characterized by comprising a polymer main chain, at least two rod-shaped liquid crystal units and a fan-shaped liquid crystal unit, wherein the polymer main chain, the two rod-shaped liquid crystal units and the fan-shaped liquid crystal unit are connected through a connecting unit.

2. The liquid crystalline polymer of claim 1, wherein at least one of said rod-like mesogens is a photoresponsive rod-like mesogen.

3. The liquid crystalline polymer of claim 1 or 2, having the structure:

wherein M is a polymer main chain, A and B are rod-shaped mesogens, C is a fan-shaped mesogen, a is a connecting unit of the main chain M and a side chain, and B and C are connecting units of the side chain.

4. The liquid-crystalline polymer of claim 1, wherein the backbone M is a polyacrylate, polyethylene, polysiloxane, polynorbornene, or polyacetylene backbone.

5. The liquid crystalline polymer of claim 3, wherein A, B has the following chemical structure:

wherein A, B have the same or different structures.

6. The liquid-crystalline polymer according to claim 1, 2, 4 or 5, wherein the mesogen segments C have a structure of the following formula 1 to formula 4:

wherein R is₁Is C₈-C₁₆Linear and branched hydrocarbon groups.

7. The liquid crystalline polymer of claim 6, wherein the linker moiety a has the structure:

wherein n is 0. ltoreq.n.ltoreq.6, and a has the same structure as b or c when n is 0, and X is not 0₁And X₂Has the same structure as b and c.

8. The liquid crystalline polymer of claim 7, wherein b and c have the following structures from formula 5 to formula 8:

wherein b and c have the same or different structures.

9. A multi-chain supramolecular columnar structure formed by the liquid crystal polymer as claimed in any one of claims 1 to 8, characterized in that: a single column contains multiple polymer chains inside, with a length on the order of microns, and a column diameter of sub-ten nanometers.

10. A method for the photo-induced orientation of multi-chain supramolecular columnar structures as claimed in claim 9, comprising the steps of:

dissolving a polymer by using a good solvent, and dripping the polymer on the surface of a clean silicon wafer for spin coating;

heating the spin-coated sample to be near the glass transition temperature at the speed of 1-20 ℃/min;

isothermal annealing was performed while maintaining the temperature and simultaneously irradiating with polarized light to induce structural orientation.

11. The method according to claim 10, wherein the good solvent is one of dichloromethane, chloroform, toluene and tetrahydrofuran;

the concentration of the polymer solution is 5-20mg/mL, and the used silicon wafers are respectively subjected to ultrasonic cleaning by deionized water, acetone and isopropanol;

the spin coating speed is 800-;

the heating rate is 10 ℃/min;

isothermal annealing with polarized light irradiation time of 15-30 min, polarized light wavelength of 250-600nm, and power of 10-1000mW/cm²。

Technical Field

The invention relates to a series of long wedge-shaped side chain liquid crystal polymers and a photoinduced orientation method of a sub-ten nanometer periodic structure of the long wedge-shaped side chain liquid crystal polymers, and belongs to the fields of high polymer materials and micro-nano processing.

Background

The side chain liquid crystal polymer and the block copolymer are two common polymer materials with microphase separation structures, and the size of the microphase separation structures meets the size requirement of micro-nano processing. The material is used for carrying out induction assembly on the surface of the substrate and carrying out pattern transfer, so that surface patterning can be realized, and the material is expected to become an auxiliary method for carrying out micro-nano processing besides the photoetching technology.

At present, the guided assembly of the block copolymer has been studied abundantly, and the surface patterning by using the guided assembly is also initially successful, but the problems of non-uniform size, high defect rate, difficulty in breaking through the size limit of the sub-ten nanometers and the like become bottlenecks which prevent the block copolymer from being further and fully applied to the field.

Compared with a block copolymer, from the theoretical research, the side chain liquid crystal polymer has the following advantages in the application of surface patterning:

firstly, the size of a microphase separation structure formed by the side chain liquid crystal polymer is determined by a side chain with an accurate chemical structure, so that the problem of cycle size fluctuation caused by molecular weight distribution is avoided;

secondly, the periodic size of the formed microphase separation structure is smaller, and the limit size of the submicron phase separation structure required by the current micro-nano processing field is more easily achieved;

and thirdly, the side chain liquid crystal polymer has the stimulation responsiveness of liquid crystal, can respond to various external stimuli, enriches the induced orientation method of the microphase separation structure, and is favorable for obtaining a periodic structure with less ordered defects.

Although the side chain liquid crystal polymer has the advantages, the application of surface patterning is rarely studied, and the main reason is that the side chain liquid crystal polymer generally has more defects and is difficult to form a long-range ordered periodic structure.

Therefore, how to eliminate the defects in the side chain liquid crystal polymer system is the key of applying the material in the field of micro-nano processing and is one of important ways for breaking through the current research bottleneck of the block copolymer system.

The long wedge-shaped side chain liquid crystal polymer is used as a novel liquid crystal polymer, can form a special columnar liquid crystal phase taking a multi-chain supermolecular column as a structural unit, a plurality of polymer chains are arranged in a single column, a main chain is positioned in the center of the column, and side chains are distributed around the column; due to the entanglement of the multiple chains, the length of the column originally limited by the chain length of the polymer is continuously prolonged, defects in the system are well eliminated, and a highly ordered columnar phase structure is formed. And the diameter of the supermolecular column can be positioned at sub-ten nanometers by controlling the size of the side chain. The photo-responsive group is introduced into the side chain, so that the photo-induced orientation of the columnar structure can be realized. The light-induced orientation of the long wedge side chain liquid crystal polymer multi-chain supermolecule columnar structure is a new development direction of sub-ten nanometer surface patterning.

Disclosure of Invention

The invention provides a long wedge-shaped side chain liquid crystal polymer and a light-induced orientation method of a sub-ten nanometer periodic structure thereof.

In order to solve the technical problems, the invention is realized by the following technical scheme:

a long wedge-shaped side chain liquid crystal polymer comprises a polymer main chain, at least two rod-shaped liquid crystal units and a fan-shaped liquid crystal unit, wherein the polymer main chain, the at least two rod-shaped liquid crystal units and the fan-shaped liquid crystal unit are connected through a connecting unit.

At least one of the rod-shaped liquid crystal elements is a photoresponsive rod-shaped element.

A long tapered side chain liquid crystalline polymer, preferably having the structure:

wherein M is a polymer main chain, A and B are rod-shaped mesogens, C is a fan-shaped mesogen, a is a connecting unit of the main chain M and a side chain, and B and C are connecting units on the side chain.

The main chain M is a polyacrylate, polyethylene, polysiloxane, polynorbornene and polyacetylene main chain.

A. B has the following chemical structure:

wherein A, B have the same or different structures.

The sectorial mesogen C has a structure of the following formula 1 to formula 4:

wherein R is₁Is C₈-C₁₆Linear and branched hydrocarbon groups.

The connection unit a has the following structure:

wherein n is 0. ltoreq.n.ltoreq.6, and a has the same structure as b or c when n is 0, and X is not 0₁And X₂Has the same structure as b and c.

b and c have the following structures of formula 5 to formula 8:

wherein b and c have the same or different structures.

The liquid crystal polymer forms a multi-chain supermolecule columnar structure, a single column internally comprises a plurality of polymer chains, and the diameter size is sub-ten nanometers.

The light-induced orientation method of the multi-chain supermolecule columnar structure comprises the following steps:

dissolving a polymer by using a good solvent, and dripping the polymer on the surface of a clean silicon wafer for spin coating;

heating the spin-coated sample to be near the glass transition temperature at a certain speed;

isothermal annealing was performed while maintaining the temperature and simultaneously irradiating with polarized light to induce structural orientation.

Wherein the good solvent is one of dichloromethane, chloroform, toluene and tetrahydrofuran;

the concentration of the polymer solution is 5-20mg/mL, and the used silicon wafers are respectively subjected to ultrasonic cleaning by deionized water, acetone and isopropanol;

the spin coating speed is 800-;

the heating rate is 10 ℃/min;

isothermal annealing with polarized light irradiation time of 15-30 min, polarized light wavelength of 250-600nm, and power of 10-1000mW/cm²。

Compared with the prior art, the technical scheme of the invention has the following advantages:

the invention provides a long wedge-shaped side chain liquid crystal polymer, wherein in a columnar phase formed by the polymer, a single column internally comprises a plurality of polymer chains, namely a multi-chain supermolecular column. Due to the entanglement of the multi-chain, the columnar structure of the polymer can continuously extend in the column axis direction, and the multi-chain structure effectively solves the problems that the columnar phase of the traditional side chain liquid crystal polymer has more defects and is difficult to form a long-range ordered periodic structure due to the limitation of molecular weight.

In addition, by utilizing the high orderliness of the multi-chain supermolecule columnar structure formed by the long wedge-shaped side chain liquid crystal polymer, a sub-ten nanometer periodic structure which can be applied to the field of micro-nano processing can be successfully constructed. The structure not only has small size, but also solves the problem of size fluctuation in a block copolymer system. More importantly, the photo-induced orientation of the columnar structure can be completed by utilizing the photo-response groups in the polymer, and compared with a chemical pattern guide assembly method of a block copolymer object, the orientation mode is simpler, more convenient and more environment-friendly.

Drawings

In order that the present invention may be more readily and clearly understood, reference will now be made in detail to the following description taken in conjunction with the accompanying drawings, in which:

FIG. 1 shows the DSC curve of polymer P1 during temperature rise

FIG. 2 is the results of small angle X-ray diffraction of P1 bulk annealed samples

FIG. 3 is an AFM photograph of P1 thin film annealed sample

FIG. 4 is a polarized UV result of a non-photo-oriented sample of P1 film

FIG. 5 is the polarized UV results of photo-oriented samples of P1 film

FIG. 6 shows AFM results for P1 thin film photo-oriented samples

FIG. 7 shows GI-SAXS results for photo-oriented samples of P1 film

FIG. 8 is a DSC curve of polymer P2 during temperature rise

FIG. 9 is the results of small angle X-ray diffraction of P2 bulk annealed samples

FIG. 10 is an AFM photograph of P2 thin film annealed sample

FIG. 11 is the polarized UV results of a non-photo-oriented sample of P2 film

FIG. 12 is the polarized UV results of photo-oriented samples of P2 film

FIG. 13 shows AFM results for P2 thin film photo-oriented samples

FIG. 14 shows the GISAXS results for the photo-oriented samples of P2 film.

Detailed Description

For a better understanding of the present invention, reference will now be made in detail to the following examples.