TWI557173B - Block copolymer - Google Patents

Description

Block copolymer

This application is directed to block copolymers.

The block copolymer has a molecular structure in which polymer subunits having different chemical structures are linked to each other by covalent bonds. The block copolymer is capable of forming a periodically aligned structure such as a sphere, a cylinder or a laminate via phase separation. The size of the structure formed by the self-assembly of the block copolymer can be adjusted within a wide range and can be made into various structural shapes. Therefore, they can be used for a method of forming a pattern by etching, various magnetic recording media or a new generation of nanodevices (such as metal dots, quantum dots or nanowires), high-density magnetic storage media, and the like.

This application provides block copolymers and their use.

"Alkyl" as used herein, unless otherwise defined, refers to an alkyl group having from 1 to 20, 1 to 16, 1 to 12, 1 to 8, or 1 to 4 carbon atoms. The alkyl group may have a linear, branched or cyclic structure, and may be optionally substituted with at least one substituent.

"Alkoxy" as used herein, unless otherwise defined, refers to an alkyl group having from 1 to 20, 1 to 16, 1 to 12, 1 to 8, or 1 to 4 carbon atoms. The alkoxy group may have a linear, branched or cyclic structure, and may be optionally substituted with at least one substituent.

"Alkenyl or alkynyl" as used herein, unless otherwise defined, refers to an alkyl group having from 2 to 20, 2 to 16, 2 to 12, 2 to 8, or 2 to 4 carbon atoms. The alkenyl or alkynyl group may have a linear, branched or cyclic structure and may be optionally substituted with at least one substituent.

"Alkylalkyl" as used herein, unless otherwise defined, refers to an alkylene group having from 1 to 20, 1 to 16, 1 to 12, 1 to 8, or 1 to 4 carbon atoms. The alkylene group may have a linear, branched or cyclic structure and may be optionally substituted with at least one substituent.

"Alkenyl or alkynyl" as used herein, unless otherwise defined, refers to an alkenyl or alkynyl group having from 2 to 20, 2 to 16, 2 to 12, 2 to 8, or 2 to 4 carbon atoms. . The alkenyl group or the alkynyl group may have a linear, branched or cyclic structure and may be optionally substituted with at least one substituent.

"Aryl or extended aryl" as used herein, unless otherwise defined, refers to a compound comprising a benzene ring structure, or includes at least two benzene rings bonded by one or two carbon atoms or by any linking group. A compound of the structure, or a derivative of the compound, derived from a monovalent or divalent substituent. Unless otherwise defined, an aryl or an aryl group can be an aryl group having 6 to 30, 6 to 25, 6 to 21, 6 to 18, or 6 to 13 carbon atoms.

As used herein, "aromatic structure" means an aryl or an aryl group.

Unless otherwise defined, "alicyclic structure" as used herein refers to a cyclic hydrocarbon structure that is not aromatic ring structure. Unless otherwise defined, the alicyclic structure may be a structure having 3 to 30, 3 to 25, 3 to 21, 3 to 18, or 3 to 13 carbon atoms.

As used herein, "single bond" refers to the absence of an atom at the relevant position. For example, the case where "B" in the structure shown by "ABC" is a single bond means that the "B" position has no atom and thus the structure shown by "AC" is directly connected to "C" by "A". .

The substituent which may be optionally substituted for an alkyl group, an alkenyl group, an alkynyl group, an alkylene group, an alkenyl group, an alkynyl group, an alkoxy group, an aryl group, an aryl group, a chain, an aromatic structure or the like may be a hydroxyl group or a halogen. Atom, carboxyl group, epoxypropyl group, propylene fluorenyl group, methacryl fluorenyl group, acryloxy group, methacryloxy group, fluorenyl group, alkyl group, alkenyl group, alkynyl group, alkylene group, alkenyl group, An alkynyl group, an alkoxy group or an aryl group, but is not limited thereto.

An exemplary block copolymer of the present application may include a block represented by the following formula 1.

In Formula 1, X ₂ is a single bond, an oxygen atom, a sulfur atom, -S(=O) ₂ -, an alkylene group, an alkenyl group, an alkynyl group, and R ₁ to R ₅ are each independently hydrogen, and have 1 An alkyl group of 8 carbon atoms, or a linear chain having 9 or more chain-forming atoms, and at least one of R ₁ to R ₅ is a linear chain of 9 or more chain-forming atoms.

In a specific embodiment, X _{2 of} Formula 1 may be a single bond or an oxygen atom; or may be a single bond, but is not limited thereto.

In Formula 1, R ₁ to R ₅ may each independently be hydrogen, an alkyl group having 1 to 8 carbon atoms, or a linear chain containing 9 or more chain-forming atoms. At least one of R ₁ to R ₅ may be a linear chain containing 9 or more chain-forming atoms.

In a specific embodiment, in R ₁ to R ₅ , R ₁ , R ₂ , R ₄ and R ₅ may each independently be hydrogen or an alkyl group having 1 to 8 carbon atoms; or may each independently be hydrogen or An alkyl group having 1 to 4 carbon atoms; or may be hydrogen; and R ₃ may be a linear chain having 9 or more chain-forming atoms.

As used herein, "chained atom" refers to a straight chain that forms certain chains. The atom of the structure. This chain may have a linear or branched structure; however, the number of chained atoms is calculated only by the number of atoms forming the longest straight chain. Therefore, in the case where other atoms are, for example, in the case where the chain-forming atom is a carbon atom, the hydrogen atom or the like which is bonded to the carbon atom is not included in the number of chain atoms. Further, in the case of branching, the number of chain atoms is the number of atoms forming the longest chain. For example, the chain is a n-pentyl group, all of the chain-forming atoms are carbon atoms and the number is five. If the chain is a 2-methylpentyl group, all of the chain-forming atoms are also carbon atoms and the number is 5. The chain-forming atoms can be carbon, oxygen, sulfur or nitrogen, and the appropriate chain-forming atoms can be carbon, oxygen or nitrogen; or carbon or oxygen. The number of chain-forming atoms may be 8 or higher, 9 or higher, 10 or higher, 11 or higher, or 12 or higher. The number of chain atoms may be 30 or lower, 25 or lower, 20 or lower, or 16 or lower.

The unit of Formula 1 allows the block copolymer to exhibit excellent self-assembly.

In a particular embodiment, the chain can be a linear hydrocarbon atom, such as a linear alkyl group. In this case, the alkyl group may be an alkyl group including 9 or more, 9 to 30, 9 to 25, 9 to 20 or 9 to 16 carbon atoms. At least one carbon atom of the carbon atom of the alkyl group may be optionally substituted with an oxygen atom; and at least one hydrogen atom of the alkyl group may be optionally substituted with another substituent.

Optionally, the linear hydrocarbyl group can include at least one hetero atom. This hetero atom may be an oxygen atom or a nitrogen atom.

This chain can be, for example, an alkyl group, an alkoxy group or an alkoxyalkyl group. In this case, the number of carbon atoms and oxygen atoms in the alkyl group, alkoxy group or alkoxyalkyl group may be 9 or more, 9 to 30, 9 to 25, 9 to 20 or 9 to 16.

Another block (hereinafter may be referred to as "second block") which is included in the block copolymer together with the first block is not particularly limited.

For example, the second block can be a polyvinylpyrrolidone block, a polylactic acid block, a polyvinylpyridine block, a polystyrene block (such as a polystyrene block or polytrimethylformamidinyl) And a polyalkylene oxide block (such as a poly(ethylene oxide block), or a polyolefin block (such as a polyethylene block or a polyisoprene block or a polybutadiene block).

In a specific embodiment, this second block can be represented by Formula 2.

The block copolymer may further comprise a second block represented by the following formula 2.

In Formula 2, R ₁ may be hydrogen or an alkyl group and R ₂ may be an alkyl group.

In a particular embodiment, R _{1 of} formula 2 can be hydrogen or an alkyl group having from 1 to 4 carbon atoms; or can be hydrogen or methyl; or can be methyl.

In a particular embodiment, R _{2 of} Formula 2 can be an alkyl group containing from 1 to 20, 1 to 16, 1 to 12, 1 to 8, or 1 to 4 carbon atoms.

A specific method of producing a block copolymer is not particularly limited as long as it comprises forming a block copolymer by using a monomer capable of forming a block The step of at least one block is sufficient.

For example, a block copolymer can be produced using a living radical polymerization (LPR) using a monomer. For example, the following method: an anionic polymerization in which a block copolymer is synthesized in the presence of a mineral acid salt such as an alkali metal or an alkaline earth metal salt, which is initiated by polymerization using an organic rare earth metal complex or an organic alkali metal compound An anionic polymerization reaction in which a block copolymer is synthesized in the presence of an organoaluminum compound, which uses an organic alkali metal compound as a polymerization initiator; atom transfer radical polymerization (ATRP), which uses atom transfer radical polymerization As a polymerization control agent; an electron-transfer (ATGET) ATRP-generated activator for polymerization, in the presence of an electron-generating organic or inorganic reducing agent, using an atom transfer radical polymerization agent as a polymerization control agent; Initiator for continuous activator regeneration (ICAR) ATRP; reversible addition-open chain transfer (RAFT) polymerization using an inorganic reducing agent reversible addition-ring-opening chain transfer agent; and using an organic ruthenium compound as an initiator The method, and a suitable method may be selected from the above methods.

In a specific embodiment, the method of producing a block copolymer may comprise polymerizing a material comprising a monomer capable of forming a block by living radical polymerization in the presence of a radical initiator and a living radical polymerization agent. .

In the manufacture of the block copolymer, a method for forming other blocks included in the block copolymer and forming a block by the above monomers is not particularly limited, and the other blocks can be considered by considering the formation to be formed The type of the segment is formed by selecting an appropriate monomer.

The method of producing a block copolymer may further comprise precipitating a polymerization product obtained by the foregoing method in a non-solvent.

The polymerization efficiency can be considered, and the kind of the radical initiator is appropriately selected without particular limitation, and an azo compound such as azobisisobutyronitrile (AIBN) or 2,2'-azobis-(2) can be used. , 4-dimethylvaleronitrile) or a peroxide compound (such as benzamidine peroxide (BPO) or di-tertiary butyl peroxide (DTBP)).

LPR can be carried out, for example, in the following solvents: dichloromethane, 1,2-dichloroethane, chlorobenzene, dichlorobenzene, benzene, toluene, acetone, chloroform, tetrahydrofuran, dioxane, dimethyl ether (monoglyme) , diethylene glycol dimethyl ether (diglyme), dimethylformamide, dimethyl hydrazine or dimethyl acetamide.

As the non-solvent, for example, an alcohol compound (such as methanol, ethanol, n-propanol or isopropanol), a diol compound (such as ethylene glycol), or an ether compound (such as n-hexane, cyclohexane, or the like) can be used without limitation. N-heptane or petroleum ether).

Since the block copolymer contains two or more polymer chains connected to each other via a covalent bond, it can be phase separated. The block copolymers of the present application exhibit excellent phase separation properties which, if desired, can be formed by microphase separation to form a nano-sized structure. The shape or size of the nano-sized structure can be controlled by the size of the block copolymer (molecular weight, etc.) or the relative ratio of the blocks. The structure formed by phase separation may include a sphere, a cylinder, a spiral tetrahedron, and a laminate and an opposite structure, and the ability to form the foregoing structure is referred to as self-assembly.

The block copolymer may have, for example, at about 3,000 to The number average molecular weight (Mn) in the range of 300,000. As used herein, "number average molecular weight" refers to the conversion value as determined by GPC (gel permeation chromatography) relative to polystyrene standards. As used herein, unless otherwise indicated, "molecular weight" as used herein refers to a number average molecular weight. In another specific embodiment, the molecular weight (Mn) may be, for example, 3000 or higher, 5000 or higher, 7000 or higher, 9000 or higher, 11,000 or higher, 13,000 or higher, or 15,000 or more. high. In another embodiment, the molecular weight (Mn) may be, for example, 250,000 or less, 200,000 or less, 180,000 or less, 160,000 or less, 140,000 or less, 120,000 or less, 100,000 or more. Low, 90,000 or lower, 80,000 or lower, 70,000 or lower, 60,000 or lower, 50,000 or lower, 40,000 or lower, 30,000 or lower, or 25,000 or lower. This block copolymer may have a polydispersity (Mw/Mn) in the range of 1.01 to 1.60. In another embodiment, the polydispersity can be about 1.1 or higher, about 1.2 or higher, about 1.3 or higher, or about 1.4 or higher.

In the above range, the block copolymer exhibits appropriate self-assembly. The target self-assembled structure can be considered to control the number average molecular weight of the block copolymer and the like.

If the block copolymer includes at least the first and second blocks, the ratio of the first block (eg, the block including the chain in the block copolymer) may range from 10 mol% to 90 mol% Inside.

This application is directed to a polymer layer comprising a block copolymer. This polymer layer can be used in a variety of applications. For example, it can be used for biosensors, recording media (such as flash memory), magnetic memory media or patterns A method of forming or a power device or an electronic device or the like.

In a specific embodiment, the block copolymer in the polymer layer can be made into a periodic structure from a self-assembly, including a sphere, a cylinder, a spiral tetrahedron, or a laminate.

For example, in a segment of a block copolymer that is linked to a first block or a second block or other block of the above block via a covalent bond, the other segments may form a regular structure, such as a laminated form, Cylindrical form, etc.

This application is also directed to a method of forming a polymer layer using a block copolymer. The method includes forming a polymer layer comprising a block copolymer in a self-assembled state on a substrate. For example, the method includes forming a layer of a block copolymer layer or a coating liquid on a substrate by a method such as coating (wherein the block copolymer is diluted in a suitable solvent, and if necessary, subsequently aging or heat-treating the layer.

This aging or heat treatment can be performed based on, for example, the phase transition temperature or the glass transition temperature of the block copolymer, and can be carried out, for example, at a temperature higher than the glass transition temperature or the phase transition temperature. The heat treatment time is not particularly limited, and the heat treatment may be performed for about 1 minute to 72 hours, but may be changed as needed. Further, the heat treatment temperature of the polymer layer may be, for example, 100 ° C to 250 ° C, but may be changed in consideration of the block copolymer used herein.

The layer formed can be aged in a non-polar solvent and/or a polar solvent at room temperature for about 1 minute to 72 hours.

This application is also directed to a method of forming a pattern. The method includes selectively removing the block copolymer from a laminate comprising a substrate and a polymer layer comprising a self-assembled block copolymer formed on the substrate The first or second block. This method can be a method of forming a pattern on the above substrate. For example, the method can include forming a polymer layer on the substrate, selectively removing one block or two or more blocks in the block copolymer (which is a polymer layer); and etching the substrate thereafter. By the above method, for example, a micro-pattern of a nanometer size can be formed. Further, depending on the shape of the block copolymer in the polymer layer, patterns of various shapes (such as nano-sticks or nanopores) can be formed by the above method. If desired, to form a pattern, the block copolymer can be mixed with another copolymer or homopolymer. The kind of the substrate to which the method is applied can be selected without particular limitation, and, for example, cerium oxide or the like can be applied.

For example, according to this method, a nano-size pattern having a high aspect ratio of cerium oxide can be formed. For example, by forming a polymer layer on ruthenium oxide, selectively removing any block of the block copolymer in a state in which the block copolymer in the polymer layer is formed in a predetermined structure, and in various methods Etching of yttrium oxide (e.g., reactive ion etching) can form various types of patterns (e.g., nano-stick or nanopore patterns). Further, according to the above method, a nano pattern having a high aspect ratio can be formed.

For example, the formed pattern size may be several tens of nanometers, and the pattern can be used for various purposes including the next generation information electronic magnetic recording medium.

For example, by the above method, a nanostructure pattern (for example, a nanowire) having a width of about 3 to 40 which is disposed at intervals of about 6 to 80 nm can be formed. In another embodiment, for example, a nanopore structure having a diameter of about 3 to 40 nm and arranged at intervals of about 6 to 80 nm can be obtained.

Further, in this structure, a nanowire or a nanopore having a high aspect ratio can be formed.

In this method, a method of selectively removing any of the blocks in the block copolymer is not particularly limited, and for example, it is possible to use a suitable electromagnetic wave (for example, ultra-ultraviolet rays) to irradiate the polymer layer to remove the relatively soft embedded layer. The method of paragraph. In this case, the conditions for the ultra-ultraviolet rays may be determined according to the block type of the block copolymer, and the ultra-ultraviolet rays having a wavelength of about 254 nm may be irradiated for 1 to 60 minutes.

In addition, after ultra-ultraviolet radiation, the polymer layer can be acid treated to further remove segments that are destroyed by the ultra-ultraviolet rays.

In addition, etching is performed on the substrate using the polymer layer from which the block is selectively removed, which can be performed by reactive ion etching using CF ₄ /Ar ions, and further oxygen can be taken after the above method The plasma treatment removes the polymer layer from the substrate.

This application provides block copolymers and their use. The block copolymer has excellent self-assembly and phase separation, and when necessary, can freely apply various desired functions.

Figure 1 shows the structure of the copolymer of Example 1 observed by AFM.

Figure 2 shows the structure of the copolymer of Example 2 observed by AFM.

Hereinafter, the present application will be described in detail with reference to the examples and comparative examples, but the scope of the present application is not limited to the following examples.

NMR analysis

NMR analysis was carried out at room temperature by using an NMR spectrometer comprising a Varian Unity Inova (500 MHz) spectrometer with a triple resonance 5 mm probe. The sample to be analyzed was diluted in a solvent (CDCl ₃ ) for NMR analysis to a concentration of about 10 mg/ml, and analyzed, and the chemical shift (δ) was expressed in ppm.

<abbreviation>

Br=broad signal, s=single peak, d=doublet, dd=two doublet, t=triplet, dt=two triplet, q=quadruple, p=fivet, m= Multiple peak

2. GPC (gel penetration chromatography)

The number average molecular weight and polydispersity were determined by GPC (gel permeation chromatography).

<GPC measurement conditions>

Device: Agilent technologies, Co.'s 1200 Series

Column: Two of PLgel mixed B using Polymer laboratories, Co.

Solvent: THF

Column temperature: 35 ° C

Sample concentration: 1mg/mL, injection 200L

Standard sample: polystyrene (Mp: 3900000, 723000, 316500, 52200, 31400, 7200, 3940, 485)

The block copolymer or macroinitiator to be determined of the examples or comparative examples was placed in a 5 mL vial and then diluted to a concentration of about 1 mg/mL. Thereafter, the standard sample for calibration and the sample to be analyzed were filtered by a syringe filter (pore size: 0.45 μm) and analyzed thereafter. ChemStation from Agilent technologies, Co., was used as an analytical program. The number average molecular weight (Mn) and the weight average molecular weight (Mw) were obtained by comparing the elution time and the calibration curve of the sample, and then polydispersity (PDI) was obtained from the ratio (Mw/Mn).

Preparation Example 1. Synthesis of p-dodecylalkylstyrene (A)

The synthesis of p-dodecylstyrene is as follows. 4-bromostyrene (5.0 g, 27.3 mmole) and Mg crumb (0.064 g, 27.31 mmole) were placed in a 100 mL bottle; dissolved in 30 mL of tetrahydrofuran in water; a small amount of iodine was added as a catalyst; Thereafter, the mixture was stirred at room temperature under nitrogen for about 6 hours to cause a reaction, and a Grignard reagent was obtained. 1-Bromododecane was placed in another 100 mL bottle, after which the above-mentioned synthesized Grignard reagent was slowly added at 0 °C. Thereafter, a dilithium tetrachlorotitanate (II) solution (8.2 mL, 0.92 mmole) was added thereto, and the bottle was heated to room temperature and the mixture was reacted by stirring for 3 hours. After the reaction, the tetrahydrofuran was removed, and the title compound was purified by column chromatography using hexane as a mobile phase to give a transparent liquid title compound (2.54 g, 9.32 mmole).

<NMR analysis results>

¹ H-NMR (CDCl ₃ ): δ 7.33 (dd, 2H); δ 7.14 (dd, 2H); δ 6.70 (dd, 1H); δ 5.71 (d, 1H); δ 5.18 (d) ,1H);δ2.59(t,2H);δ1.60(p,2H);δ1.31-1.26(m,18H);δ0.89(t,3H)

Preparation 2. Synthesis of p-dodecyloxymethylstyrene (B)

The synthesis of p-dodecyloxymethylstyrene (B) is as follows. 4-Chloromethylstyrene (22.1 g, 144.8 mmole) and 1-dodecyl alcohol (30.0 g, 160.1 mmole) were dissolved in 300 mL of tetrahydrofuran and then cooled to 0 °C. Sodium hydride (NaH) (7.7 g, 320.8 mmole) was added thereto; the mixture was reacted by stirring for 1 hour; the mixture was heated to 70 ° C and then reacted for 24 hours. After the reaction, the reaction product was cooled to room temperature, and the remaining sodium hydride was removed by reacting with a small amount of water in ice water, and the solid was removed by filtration. The tetrahydrofuran as a reaction solvent was removed; the organic layer was collected by a step-by-step extraction using dichloromethane/second purified water, by column chromatography using hexane/dichloromethane as a mobile phase to give a transparent liquid standard compound. (23.9 g, 79.0 mmole).

<NMR analysis results>

¹ H-NMR (CDCl ₃ ): δ 7.39 (dd, 2H); δ 7.30 (dd, 2H); δ 6.71 (dd, 1H); δ 5.74 (d, 1H); δ 5.23 (d, 1H);δ4.49(s,2H);δ3.46(t,2H);δ1.61(p,2H);δ1.37-1.26(m,16H);δ0.89(t,3H)

Example 1

By using methyl methacrylate with RAFT (reversible addition-cleaving chain transfer agent) reagent and AIBN (azo group) as thermal initiator Double isobutyronitrile) reaction, synthesis of macroinitiator (number average molecular weight (Mn): 7000, polydispersity (PDI): 1.16). The synthesized macromolecule initiator, the compound (A) prepared in Preparation Example 1, and the azobisisobutyronitrile (AIBN) are dissolved at a weight ratio of 1:70:0.5 (macromolecule initiator: compound (A): AIBN). The block copolymer was obtained by reacting in toluene (solvent: 20% by weight), followed by reaction at 80 ° C for 16 hours under nitrogen. This block copolymer had a number average molecular weight of 19,200 and a polydispersity of 1.17.

Example 2

A macroinitiator (quantitative average molecular weight (Mn): 8400, polydispersity (PDI): 1.15) was synthesized by the same method as described in Example 1, and then prepared by the same method as described in Example 1. The block copolymer was used, but the compound (B) in Preparation Example 2 was used instead of the compound (A) in Preparation Example 1. The block copolymer had a number average molecular weight of 2,1900 and a polydispersity of 1.19.

Test example 1

Coating solution prepared by dissolving the block copolymer of Example 1 or 2 at about 1.0% by weight in toluene on a ruthenium wafer using a spin coater at 3000 rpm for 60 seconds to form a polymer Floor. This polymer layer was heat-treated at 160 ° C for 1 hour, whereby a nanostructure was realized on the surface thereof. The nanostructure realized by AFM (atomic force microscope) was observed. Figure 1 is the result of Example 1 and Figure 2 is the result of Example 2.

Claims (9)

A block copolymer comprising a first block of the following formula 1: Wherein X ₂ is a single bond, an oxygen atom, a sulfur atom, -S(=O) ₂ -, an alkylene group, an alkenyl group, an alkynyl group, and R ₁ to R ₅ are each independently hydrogen, having 1 to 8 An alkyl group of a carbon atom or a straight chain having 9 or more chain-forming atoms, and at least one of R ₁ to R ₅ is a linear chain having 9 or more chain-forming atoms, and wherein the group has 9 or More straight chain-forming atoms are alkyl, alkoxy or alkoxyalkyl. The block copolymer of claim 1, wherein X ₂ is a single bond or an oxygen atom. The block copolymer of claim 1, wherein the linear chain comprises from 9 to 30 chain-forming atoms. The block copolymer of claim 1, which further comprises the second block of the following formula 2: Wherein R ₁ is hydrogen or alkyl and R ₂ is alkyl. The block copolymer of claim 4, wherein R ₁ of the formula 2 is an alkyl group having 1 to 4 carbon atoms. The block copolymer of claim 4, wherein R ₂ of the formula ₂ is an alkyl group having 1 to 4 carbon atoms. A polymer layer comprising the self-assembled product of the block copolymer of claim 1 of the patent application. A method of forming a polymer layer comprising forming a polymer layer comprising a self-assembled product of the block copolymer of claim 1 of the patent application. A method of forming a pattern comprising selectively removing a laminate comprising a substrate and a polymer layer formed on the substrate comprising a self-assembled product of the block copolymer of claim 1 A first block in the block copolymer or a second block different from the first block.