KR20160003983A - Polythiophene based-grafted copolymer and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a polythiophene graft copolymer and a method for preparing the same. More specifically, the polythiophene graft copolymer is formed by performing a microwave-assisted click reaction on a first polymer of polythiophene having an azide group attached thereto and a conjugate in which an alkyne group is attached to the end thereof. The method for preparing the polythiophene graft copolymer according to the present invention comprises the following steps: (a) preparing a first polymer in which thiophene having an alkyl group attached thereto is polymerized and a predetermined conjugate; and (b) forming a copolymer in which the conjugate is grafted to the first polymer through a click reaction. Herein, the conjugate may be a second polymer which can be formed by a chain growth polymerization, a macromolecule, or a luminescent unimolecule. In this case, the azide group is introduced to the end of a part or the entirety of the alkyl group, and the alkyne group is introduced to the end of the conjugate, thus the alkyne group forms a junction structure while reacting with the azide group.

Description

TECHNICAL FIELD [0001] The present invention relates to a polythiophene based graft copolymer and a manufacturing method thereof,

The present invention relates to a conjugated copolymer based on polythiophene and a method for producing the same. More particularly, the present invention relates to a conjugated copolymer having a polythiophene first polymer having an azide group and an alkyne group attached to the terminal, The present invention relates to a polythiophene-based conjugated copolymer formed through a microwave-assisted click reaction and a method for producing the same.

Recently, various applications using organic materials such as organic materials, solar cells, and flexible displays have attracted much attention. In the case of organic solar cells, it is possible to significantly reduce the production cost by using an inexpensive organic material and a solution process and a roll-to-roll technique. Because of the low temperature process, It can be advantageous in that it can be manufactured in a light and flexible form using a substrate. In addition, continuous efforts have been made to implement and improve a flexible display capable of forming an organic field effect transistor (Organic FET) using an organic material and further improving the convenience of the user.

In this regard, a self-assembled block copolymer having an ordered structure can form a wide interface and a continuous charge transfer path, and thus can be used as an active layer in the field of organic electronic materials having high efficiency It is one of the most promising candidates. At this time, a block copolymer composed of a conjugated polymer may be used to make the self-assembled block copolymer having the aligned structure, which is a difficult process. This is because strong rod-rod interaction between the conjugated polymers prevents the formation of aligned structures. When the conjugated polymers are greatly affected by rod-rod interaction, it becomes difficult to form an aligned structure by forming a long fiber-like thread structure of fibril shape, And the characteristic as an organic material electronic material is also deteriorated.

In more detail, a rod-coil block copolymer composed of a conjugated polymer has a phase behavior, unlike a typical coil-coil block copolymer, Is difficult to predict. This is because the conjugated polymers having excellent electrical properties usually have a strong crystallinity, and thus the copolymer to be synthesized exhibits strong rigidity. Thus, the creation of nanostructures with continuous nanoscopic and large-area interfaces from electroactive copolymers has long been a topic of interest.

Particularly, among the various candidate groups that can be used as a conjugate block, there are materials composed of polythiophene. For example, regioregular poly (3-hexylthiophene) (P3HT) is one of the most interesting research subjects because it has excellent properties in both organic solar cell and organic thin film transistor . However, many of the reported P3HT-based copolymers such as P3HT-block-poly (styrene, 2-vinylpyridine, 4-vinylpyridine, acrylic acid, methyl acrylate, lactide) showed mostly fibril- The moiety is crystallized to have a long fiber shape and is buried in an amorphous coil block region to form an irregular structure and thus the characteristic as an electronic material is also deteriorated.

Further, researches for imparting a predetermined functionality (for example, solubility and luminescence properties) required for application to a predetermined application to the polythiophene-based copolymer have been continued, but an appropriate solution has yet to be presented It is a fact that it does not become.

Accordingly, it is possible to provide a copolymer having a structure aligned on the basis of a polythiophene, and also to provide a structure having a nonfibril shape by suppressing rod-rod interaction between polythiophenes Or a polythiophene-based copolymer capable of imparting a predetermined functionality to the polythiophene-based copolymer, and a process for producing the same. However, a proper solution has not yet been proposed.

One embodiment of the present invention is to solve the above-mentioned problems of the prior art, and it is an object of the present invention to provide a polythiophene-based copolymer which is capable of realizing rod-rod interaction between polythiophenes, And a method of preparing the polythiophene-based copolymer. The present invention also provides a polythiophene-based copolymer comprising the polythiophene-based copolymer and the polythiophene-based copolymer.

Another embodiment of the present invention provides a polythiophene-based copolymer imparted with a predetermined functionality such as solubility or luminescence by forming a copolymer to which a predetermined conjugate is bonded based on polythiophene and a process for producing the same The purpose.

According to one aspect of the present invention, there is provided a method for preparing a conjugated copolymer comprising: (a) preparing a first polymer having a thioephene group attached with an alkyl group and a predetermined conjugate ; And (b) forming a grafted copolymer of said conjugate on said first polymer through a click reaction, wherein said conjugate is formed by chain growth polymerization An azide group is introduced at the terminal of a part or all of the alkyl group, and an alkyne group is added to the terminal of the conjugate at the terminal of the second polymer, And the alkyne group reacts with the azide group to form a bonding structure.

Here, the number of carbon atoms contained in the alkyl group may be in the range of 4 to 12.

In addition, when the second polymer is used as the conjugate, the interaction between the first polymers can be controlled by using the length or the density of the second polymer.

When the second polymer is used as the conjugate, the second polymer may be selected from the group consisting of polystyrene, poly (2-vinylnyridine) (P2VP), P4VP, poly (methyl methacrylate) , Polybutadiene, or a mixture of two or more thereof.

In the step (b), the first polymer and the conjugate may be dissolved in a predetermined solvent to proceed a click reaction.

In addition, one of tetrahydrofuran or chloroform may be used as the solvent.

Also, in the step (b), a copolymer may be formed through a high frequency-assisted click reaction.

Also, the first polymer is poly (3-hexylthiophene) and the conjugate is P2VP, thereby forming a P3HT-g-P2VP copolymer in step (b).

Here, the ordered structure can be formed by setting the volume ratio of P3HT to the P3HT-g-P2VP copolymer to 60% or less.

In addition, the volume ratio of P3HT to the P3HT-g-P2VP copolymer can be controlled through the molecular weight of the P2VP.

According to another aspect of the present invention, a conjugated copolymer comprises a backbone comprising a first polymer polymerized with an alkyl group-attached thioephene; And a conjugate that is grafted to some or all of the monomers of the first polymer, wherein the conjugate is a second polymer that can be formed by chain growth polymerization, a polymer, And is a luminescent monomolecule.

Wherein the second polymer is one or more of polystyrene, poly (2-vinylryridine), P4VP, poly (methyl methacrylate), polyactide, polybutadiene Or more.

Also, the first polymer is poly (3-hexylthiophene), the conjugate is P2VP, and the volume ratio of P3HT to the P3HT-g-P2VP copolymer thus formed is 0.6 or less, wherein the P3HT- The g-P2VP copolymer may have an ordered structure.

A flexible display according to another aspect of the present invention is characterized in that it comprises an organic field effect transistor (organic FET) comprising the above-mentioned conjugated copolymer.

According to one embodiment of the present invention, a copolymer is prepared by subjecting a first polymer of an azide group-attached polythiophene and a second polymer having an alkyne group at its terminal end to a microwave-assisted click reaction Based on a polythiophene-based conjugated copolymer having an ordered structure by inhibiting rod-rod interaction between polythiophenes by adjusting the molecular weight of the second polymer to a predetermined range, Method.

According to another embodiment of the present invention, there is provided a polythiophene-based conjugated copolymer imparted with a predetermined functionality such as solubility or luminescence by forming a copolymer to which a predetermined conjugate is bonded based on polythiophene and a method for producing the same .

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
1 is an explanatory view of a synthesis process of a P3HT-g-P2VP copolymer according to an embodiment of the present invention.
2 is a flowchart of a method for producing a P3HT-g-P2VP copolymer according to an embodiment of the present invention.
3 is an explanatory diagram of a synthesis process of a P3HT-azide polymer according to an embodiment of the present invention.
FIG. 4 is an explanatory diagram illustrating a structural change according to the structure of P3HT-g-P2VP copolymer and the ratio of P3HT according to an embodiment of the present invention.
5 is a cross-sectional scanning electron microscope (TEM) image of a P3HT-g-P3VP copolymer with a ratio of P3HT according to an embodiment of the present invention.
Figure 6 is a second periodic heating and cooling differential scanning calorimetry (DSC) thermogram of P3HT-azide and P3HT-g-P3VP copolymers according to one embodiment of the present invention.
7 is a graph of crystallization temperature and crystallization degree of P3HT-g-P3VP copolymer by P2VP molecular weight according to an embodiment of the present invention.
FIG. 8 is a graph showing the out-of-plane line (X-ray) curves of the P3HT-azide and P3HT-g-P3VP copolymers according to one embodiment of the present invention cuts) graph.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is capable of various modifications and various embodiments, and specific embodiments will be described in detail below with reference to the accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The terms first, second, etc. may be used to describe various components, but the components are not limited by the terms, and the terms are used only for the purpose of distinguishing one component from another Is used.

The present invention is based on the finding that when a self-assembled block copolymer is constructed using a conjugated polymer according to the prior art, strong rod-rod interaction between the conjugated polymer The present inventors have found that the first polymer of the polythiophene having an azide group and the first polymer of the polythiophene having an azide group are mixed with the first polymer of the polythiophene having an azide group to form an irregular structure, A copolymer is prepared through a microwave-assisted click reaction on a second polymer to which an alkene group is attached at the end, by adjusting the molecular weight of the second polymer to a predetermined range, Disclosed is a polythiophene-based conjugated copolymer having an ordered structure inhibiting rod-rod interaction and a method for producing the same. And that is characterized.

The present invention also relates to a polythiophene-based conjugated copolymer capable of imparting certain functionality (e.g., solubility, luminescence properties, etc.) required for application in a given application to a polythiophene- And a process for producing the same.

Before a detailed description of the present invention, an overview of the present invention, such as an approach for forming a self-assembled block copolymer having an aligned structure using a conjugated polymer, .

As previously discussed, rod-rod interaction between conjugated polymers results in a long fibril-shaped filament-like thread structure due to the high rigidity of the polymer, . On the contrary, the rod-coil copolymer of the graft type according to the present invention is one of good candidate structures to solve this problem.

The self-assembling behavior of rod-coil copolymers can be measured using the Flory-Huggins interaction ( χN ), Maier-Saup type rod- -rod) is closely related to the balance between the interaction ( μN ) and the chain entropy. For example, the phase of a regioregular P3HT (poly (3-hexylthiophene)) based copolymer The phase behavior is mainly determined by the Maier-Saupe type rod-rod interaction due to the strong rigidity of the P3HT rod. Thus, Only the fibril-type shape is observed after the heat treatment, irrespective of the kind and the volume ratio of the P3HT. However, recently, in the case of modifying the chemical structure of P3HT using an alkyl chain, (rod-rod interaction), and accordingly, various kinds (2'-ethyl) -hexylthiophene) -block-polyac-tide (P3EHT-b-PLA) copolymers have been reported to be capable of forming nonfibril self- (3-dodecylthiophene) -block-poly (methyl methacrylate), which is a well-ordered lamellar and cylindrical microstructure by self-assembly by inserting an ethyl branch into the alkyl chain ) (P3DDT-b-PMMA) copolymers have been reported.

However, when the chemical structure of P3HT is modified, the electrical characteristics of the organic electronic device generally become poor. Thus, a method for systematically controlling the rod-rod interaction of P3HT-based copolymers without modifying the chemical structure of P3HT is to use an ordered structure self-assembling block copolymer based on P3HT And further, it is an important basis for application to the field of organic electronic materials based on polythiophene including P3HT.

In addition, the molecular structure of the copolymer is a very important factor in determining the shape and thermal properties of the copolymer. One of the various types of aligned nano-shaped copolymers that have been of interest to researchers is graft copolymers, and studies on the phase behavior characteristics of the conjugated copolymers are underway. For example, a conjugated copolymer composed of a backbone composed of polyisoprene (PI) or polybutadiene (PB) and a polystyrene (PS) chain bonded thereto is synthesized And a nanostructure similar to that of a conventional two-block copolymer was observed. Along with the geometrical aspects, the melting behavior of the conjugated copolymers is also greatly influenced by the grafting density and the molecular weight of the grafted segment. As the length of the chain to be joined increases, or as the bonding density increases, the melting point changes, which means that the chain to be bonded can affect the crystallization of the backbone block. Taking this into consideration, introducing a conjugation structure to a polythiophene-based rod-coil copolymer containing P3HT and the like modulates the rod-rod interaction, It can be inferred that it may be an appropriate alternative for synthesizing an ordered structure of various formation.

Furthermore, by forming a copolymer to which a predetermined conjugate is bonded based on polythiophene, a polythiophene-based conjugated copolymer imparted with a predetermined functionality such as solubility or luminescence can also be formed .

Hereinafter, exemplary embodiments of a polythiophene-based rod-coil copolymer having an aligned structure according to the present invention and a method of manufacturing the same will be described in detail with reference to the accompanying drawings.

First, FIG. 1 illustrates a process of synthesizing a P3HT-g-P2VP copolymer according to an embodiment of the present invention. As can be seen in FIG. 1, the P3HT-g-P2VP copolymer has a high frequency-assisted click response between the P3HT-azide polymer and the P2VP-alkyne polymer synthesized according to the controlled polymerization method (microwave-assisted click reaction).

Herein, a copolymer synthesized by bonding P3HT and P2VP is exemplified. However, the present invention is not limited thereto. More generally, a first polymer in which thioephene having an alkyl group attached thereto is polymerized, chain polymerization of a second polymer which is capable of forming a copolymer, wherein an azide group is attached to a terminal of a part or all of the alkyl groups, and the second polymer An alkyne group is attached to the terminus of the alkyne group so that the alkyne group reacts with the azide group to form a bonding structure.

At this time, it is appropriate that the alkyl group attached to the first polymer contains 4 to 12 carbon atoms in consideration of the rigidity and thermal characteristics of the copolymer formed by using the alkyl group. More specifically, the second polymer may be one selected from the group consisting of polystyrene, poly (2-vinylryridine), P4VP, poly (methyl methacrylate), polyactide, polybutadiene, It is also possible to use a mixture of two or more.

FIG. 2 is a flowchart illustrating a method for producing a P3HT-g-P2VP copolymer according to an embodiment of the present invention. The method of preparing a P3HT-g-P2VP copolymer according to an embodiment of the present invention includes a step S210 of producing a P3HT-azide polymer by Grignard Metathesis polymerization, a step of RAFT polymerization Step S230 of preparing a P2VP-alkene polymer by a method (S220) and a step S230 of producing a P3HT-g-P2VP copolymer through a high-frequency-assisted click reaction .

Here, the P2VP may be replaced with a polymer or a luminescent monomolecule to form a copolymer in which a polymer or a luminescent monomolecule is bonded to P3HT. In this case, as in the case of P2VP, the polymer or the luminescent monomolecule has an alkyne group introduced at the terminus thereof and forms a bonding structure by reacting with an azide group of the P3HT-azide polymer through a click reaction. By forming a copolymer in which P3HT is conjugated with a polymer or a luminescent monomolecule, a predetermined functionality such as solubility or luminescence can be imparted to the copolymer in which the polymer or the luminescent monomolecule is bonded to the P3HT.

In addition, the interaction between the P3HT and the P3HT can be controlled by controlling the density and the length of the polymer or the luminescent monomers in the copolymer in which the P3HT is conjugated with the polymer or the luminescent monomolecule.

Hereinafter, a method for producing a P3HT-g-P2VP copolymer according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 and 2. FIG.

First, a P3HT-azide polymer is synthesized (S210) through Grignard Metathesis (GRIM) polymerization. At this time, it is preferable that the azide group has a low polydispersity index (PDI) value in consideration of effective synthesis of the P3HT-g-P2VP copolymer and formation of an aligned structure. In one embodiment of the present invention, a 3- (azidohexyl) thiophene monomer randomly distributed in a P3HT backbone was controlled in a proportion of 5 mol%. Further, the P3HT-azide polymer is not necessarily synthesized by Grignard Metathesis (GRIM) polymerization method, and can be applied without any particular limitations as long as it can appropriately synthesize a P3HT-azide polymer. Do.

A detailed description of a method for synthesizing a P3HT-azide polymer using the Grignard metathesis (GRIM) polymerization method is as follows. FIG. 3 illustrates a synthesis process of a P3HT-azide polymer according to an embodiment of the present invention. In order to synthesize the P3HT-azide polymer, 2,5-dibromo-3- (6-bromohexyl) thiophene) and 2,5- Starting from a mixture of dibromo-3-hexylthiophene. The mixture is mixed with isopropyl-magnesium chloride in the range of 0 to 20 degrees Celsius with tetrahydrofurane (THF) as a solvent in an inert gas atmosphere such as nitrogen, argon and the like.

Subsequently, a Ni (dppp) Cl2 suspension as a polymerization initiator is added to the mixture to initiate the polymerization reaction. An acid solution such as hydrochloric acid or nitric acid is added to the mixture to quench the polymerization reaction, neutralize the acidity of the solution with a basic solution such as ammonia, and then filter.

The poly (3-hexylthiophene) polymer such as methanol, ethanol, and hexane does not dissolve and the impurities such as oligomers are dissolved. After removal of the impurities by Soxhlet extraction method and drying, P3HT- It is possible to obtain a P3HT-bromine polymer which is an intermediate of the zeol polymer.

The P3HT-bromopolymer is then dissolved in a solvent that can be used for crystal induction in solution, for example, in a solvent selected from tetrahydrofuran (THF) or chloroform, and nitrided to form an azide group In order to dissolve sodium (NaN ₃ ) and 18-crown-6 in a polar solvent such as alcohol and dihydro furane (DMF) uniformly, the azide ion can be transferred to the solvent selected in the polar solvent. (4, 7, 10, 13, 16-hexaoxacyclooctadecane), which is a phase transfer agent, maintained at 40 to 50 degrees Celsius and maintained in an inert gas atmosphere for about 8 hours, And mixed with the bromine polymer solution. Thereafter, the mixed solution is filtered, and impurities including residual sodium nitrite (NaN ₃ ) are removed by the Soxhlet extraction method using alcohol such as methanol or ethanol as a solvent, and vacuum drying is performed to obtain P3HT-azide.

In addition, the P2VP-alkyne polymer may be synthesized through Reversible Addition-Fragmentation Transfer (RAFT) polymerization (S220). The synthesis of the P2VP-alkyne polymer using the RAFT polymerization method can be carried out without difficulty according to the prior art, so that it is not discussed in detail here. An alkyne-terminated RAFT chain transfer agent can also be prepared according to the prior art.

In this case as well, the P2VP-alkyne polymer is not necessarily synthesized by the Reversible Addition-Fragmentation Transfer (RAFT) polymerization method, and if the P2VP-alkyne polymer can be appropriately synthesized, It is possible.

The P2VP-alkyne polymer is then coupled with the P3HT-azide polymer via a copper (I) -catalyzed click reaction to form a mixture of various P3HT volume fractions from 1 to 0.19 ) (f _P3HT ) is synthesized (S230). In proceeding with the click reaction, it is preferable that the P3HT-azide polymer and the P2VP-alkene polymer are dissolved in a solvent such as THF or chloroform.

At this time, the azide group is known as a cross-linkable unit which is effectively crosslinked by light or heat, so that the click reaction between the P3HT-azide polymer and the P2VP-alkene polymer is completed Is very important. Thus, in order to suppress the possibility of self-cross-linking between the P3HT-g-P2VP copolymers due to the presence of unreacted azides of the P3HT-g-P2VP copolymer, a high- microwave-assisted click reaction).

FIG. 4 illustrates a structural change according to the structure of the P3HT-g-P2VP copolymer 400 and the ratio of P3HT according to an embodiment of the present invention. As shown in FIG. 4 (a), the P3HT-g-P2VP copolymer 400 according to an embodiment of the present invention includes a poly (3-hexylthiophene) polymer (P3HT) (P2VP) (420) that is grafted to a backbone and a monomer of the P3HT polymer (410). The molecular weight of the P2VP (420) M _{n, P2VP)} or in P3HT-g-P2VP by adjusting the volume ratio (f _P3HT) of P3HT to less than a predetermined threshold value for the copolymer (400), Brill blood, as can be seen in Fig. 4 (b) in accordance with it becomes possible to form an aligned structure such as a lamellar, a cylinder and the like out of the irregular structure of the fibril shape.

However, similar to the above, the present invention is not limited to the P3HT-g-P2VP copolymer (400), and more generally, a first polymer in which thioephene with an alkyl group attached is polymerized A backbone comprising; And a second polymer that is grafted to some or all of the monomers of the first polymer, wherein the second polymer is selected from the group consisting of polystyrene, poly (2-vinylryridine) (P2VP) ), P4VP, PMMA (poly (methyl methacrylate)), polyactide, polybutadiene, or the like, or a mixture thereof.

At this time, the second polymer may be replaced with a polymer or a luminescent monomer. In this case, the copolymer having the P3HT conjugated with the polymer or the luminescent monomolecule can be given a predetermined functionality such as solubility and luminescence necessary for application in a predetermined application. In addition, the interaction between the P3HT and the P3HT can be controlled by controlling the density and the length of the polymer or the luminescent monomers in the copolymer in which the P3HT is conjugated with the polymer or the luminescent monomolecule.

(M _{n , P2VP} ) of various bonded P2VP chains, while having a similar bonding density and a similar level of polydipersity index (PDI) value as embodiments of the present invention, a series of P3HT-graft-P2VP (P3HT-g-P2VP) copolymers having a volume fraction (f _P3HT ) were prepared.

A series of P2VP-alkyne polymers having molecular weights (M _{n , P2VP} ) of conjugated P2VP chains of varying values, with similar polydispersity index (PDI <1.2) To prepare a P3HT-g-P2VP copolymer. At this time, the P2VP chain bonded to one polymer was regulated to about 2, and the molecular weight of P2VP (M _{n , P2VP} ) and thus the P3HT volume ratio (f _P3HT ) were systematically controlled.

At this time, control the molecular weight (M _{n, P2VP)} value of P2VP in P3HT-g-P2VP by bars between P3HT - could adjust the rod cross-reaction (rod-rod interaction), Accordingly, plate-shaped (lamellar), cylinder (cylinder (TEM) and X-ray scattering (X-ray scattering), which can form various kinds of aligned shapes including a sphere and a sphere. In addition, the fact that the P3HT rod-rod interaction can be controlled through the molecular weight change of P2VP indicates that differential scanning calorimetry (DSC), which shows the change of crystal properties of P3HT-g-P2VP copolymer, And grazing incidence wide angle X-ray scattering (Grazing Incidence Wide-Angle X-ray Scattering, GI-WAXS).

Table 1 below summarizes the properties of the synthesized P3HT-g-P2VP copolymers.

P3HT-gP2VP conjugated copolymer Bonding density [mol%] P3HT molecular weight _{(M n, P3HT) [g} / mol] P3HT PDI P2VP molecular weight _{(M n, P2VP) [g} / mol] P2VP PDI f _P3HT rescue D [nm] P3HT-azide 5.2 6.8K 1.19 - - 1.00 - - P3HT-g-P2VP (2.0) 2.0K 1.15 0.63 Fibril 12.5 P3HT-g-P2VP (4.4) 4.4K 1.13 0.45 Plate type 18.0 P3HT-g-P2VP (7.1) 7.1K 1.10 0.33 Cylindrical 20.8 P3HT-g-P2VP (8.4) 8.4K 1.21 0.29 Cylindrical 22.1 P3HT-g-P2VP (9.5) 9.5K 1.12 0.27 Cylindrical 24.9 P3HT-g-P2VP (12.2) 12.2K 1.13 0.22 rectangle 26.2 P3HT-g-P2VP (15.1) 15.1K 1.25 0.19 rectangle 27.3

The self-assembly properties of P3HT-g-P2VP copolymers according to the molecular weight of the _P2VP (M _n, P2VP) are used to cross-sectional scanning electron microscope (cross-sectional TEM) and grazing incidence angle wide-angle X- ray scattering (GI-WAXS) Can be confirmed from the features of the identified shape. FIG. 5 shows a cross-sectional scanning electron microscope (TEM) photograph of a P3HT-g-P3VP copolymer having a ratio of P3HT according to an embodiment of the present invention. As can be seen in FIG. 5 (a), P3HT-g-P2VP (2.0) with a short P2VP chain (f _P3HT = 0.63) showed a fibril-like shape. In addition, the in-plane line cut of the corresponding grating angle incident wide angle X-ray scattering (GI-WAXS) has a very wide peak and a domain spacing of 12.5 nm due to the irregular structure (d ). Although the fibril-like structure of crystals common to P3HT-based block copolymers can be observed, fibrils are much shorter. However, rod-rod interaction is still more prominent than other factors that determine phase behavior, and the strong crystallization of the P3HT moiety leads to the formation of well aligned microstructures And a fibril-like structure is formed. Thus, by setting the volume ratio of P3HT to P3HT-g-P2VP copolymer to be less than 60%, the influence of rod-rod interaction can be reduced, and thus the P3HT-g-P2VP copolymer Can be adjusted to an aligned morphology.

As the molecular weight of P2VP (M _{n , P2VP} ) increased from 2.0 to 4.4 kg / mol, the heat treated P3HT-g-P2VP (4.4) copolymer (f _P3HT = 0.45) lamellar structure (Fig. 5 (b)). At this time, the plate-like structure of the P3HT-g-P2VP (4.4) copolymer extends to the micrometer level and has a continuous and long shape. At the same time, the corresponding in-plane line cut of GI-SAXS showed a much sharper peak when the domain spacing d value was 18 nm. In this composition, the rod-rod interaction of the P3HT block is considerably reduced, and a plate-like shape having a clear boundary can be formed.

When the molecular weight of P2VP (M _{n , P2VP} ) is further increased, the P3HT-g-P2VP copolymer having a volume ratio (f _P3HT ) of _P3HT of 0.33, 0.29 and 0.27 is hexagonally packed cylinder-shaped P3HT structure (FIG. 5 (c)). At this time, the domain interval (d) value of P3HT-g-P2VP was measured to be 20.8, 22.1 and 24.9, respectively, when the volume ratio (f _P3HT ) of _P3HT was 0.33, 0.29 and 0.27, The larger the domain spacing (d) value was recorded. Scanning electron microscope (TEM) photographs show that hexagonally packed domains form parallel or perpendicular to the substrate, forming P3HT cylinder particles in mono-orientation regions. The grain boundary at this time can be clearly distinguished as indicated by the white line in Fig. 5 (c).

In the larger P2VP volume ratio (f _P3HT = 0.22, 0.19), a spherical shape was observed as shown in FIG. 5 (d), which was slightly unaligned at this time. This is attributed to the random distribution of junction points that cause packing frustration due to the stiffness of the P3HT block.

The effect of rod-rod interaction and shape on the P3HT-g-P2VP copolymer due to P2VP chain bonding was investigated by differential scanning calorimetry (DSC) using P3HT-g-P2VP copolymer A more detailed review is possible by looking at the thermal properties. A second periodic thermogram of heating and cooling for the P3HT-azide polymer and a representative P3HT-g-P2VP copolymer is shown in Figure 6 and the thermal properties of the P3HT-g-P2VP copolymer are shown in Table 2 below .

Bonded copolymer Tm [[deg.] C] Tc [[deg.] C] ΔH _m [J / g] Crystallinity [%] P3HT-azide 203 148 14.60 14.74 P3HT-g-P2VP (2.0) 188 137 8.07 8.15 P3HT-g-P2VP (4.4) 188 131 4.54 4.58 P3HT-g-P2VP (7.1) 187 118 2.42 2.44 P3HT-g-P2VP (8.4) 180 109 2.04 2.07 P3HT-g-P2VP (9.5) 176 105 1.80 1.81 P3HT-g-P2VP (12.2) 177 116 1.72 1.73 P3HT-g-P2VP (15.1) 180 112 1.62 1.64

As can be seen in FIG. 6 and Table 2, the P3HT-azide polymer dissolves at 203 ° C during the heating process, while the P3HT-g-P2VP copolymer has a melting endothermic peak (Tm) ° C. In addition, as the molecular weight of P2VP (M _{n , P2VP} ) increased, the soluble endothermic peak (Tm) value of P3HT-g-P2VP gradually decreased and at the same time, about 105 The peak at &lt; RTI ID = 0.0 &gt; 0 C &lt; / RTI &gt; The cooling process also showed a similar tendency in the crystallization temperature (Tc) of the P3HT block of the P3HT-g-P2VP copolymer. The crystallization temperature (Tc) values in P3HT-azide, P3HT-g-P2VP (2.0), P3HT-g-P2VP (4.4) and P3HT- Respectively. This decrease in the dissolution endothermic peak (Tm) and at the crystallization temperature (Tc) is due to the fact that as the longer P2VP chain is added, the P3HT moiety in the conjugated copolymer becomes weaker rod-rod interaction ).

Quantitative analysis of the effect of the bonding P2VP chain on the crystallization properties of the P3HT-g-P2VP copolymer can be obtained by calculating the degree of crystallinity thereof (Fig. 7). The crystallinity was measured by heat fusion (? H _m ) of the P3HT-g-P2VP copolymer calculated by differential scanning calorimetry (DSC) thermogram and heat fusion of pure P3HT crystals (? H _mo = 99J / g ). &Lt; / RTI &gt; The crystallinity of the P3HT-azide polymer was measured to be 14.7%, which is consistent with the reported values in conventional studies. After the molecular weight (M _{n, P2VP)} value of the P2VP was respectively 2.0, 4.4, 15.1kg / mole P2VP block bonding (grafting) a, was calculated in each of the degree of crystallinity 8.2%, 4.6%, 1.6%. The thermal properties of the P3HT-g-P2VP copolymer, including heat of fusion and crystallinity, are also summarized in Table 2 above.

In addition, UV-vis absorption spectra for P3HT-azide polymers and P3HT-g-P2VP copolymers were measured and the resulting optical properties are summarized in Table 3 below. Reducing the blue shift and peak vibronic peak intensity of the maximum peak supports the reduction of the P3HT rod-rod interaction with increasing molecular weight (M _{n , P2VP} ) values of _P2VP . Therefore, the bonding method according to the present invention can control the P3HT rod-rod interaction by simply changing the molecular weight (M _{n , P2VP} ) value of _P2VP , and accordingly the P3HT-g-P2VP copolymer It is possible to confirm that it can control both the thermal and the shape characteristics of the substrate.

Bonded copolymer λ _max [nm] I _vib / I _max P3HT-azide 550 0.69 P3HT-g-P2VP (2.0) 511 0.35 P3HT-g-P2VP (4.4) 509 0.34 P3HT-g-P2VP (7.1) 506 0.32 P3HT-g-P2VP (8.4) 503 0.27 P3HT-g-P2VP (9.5) 501 0.25 P3HT-g-P2VP (12.2) 493 0.19

Furthermore, in order to investigate the effect of the P2VP chain on the structure of the P3HT-g-P2VP copolymer, various rod-rod interactions (GI-WAXS) rod interaction value of P3HT-g-P2VP (FIG. 8). A thin film polymer at a level of about 100 nm was subjected to a heat treatment process in the same manner as in the above-mentioned scanning electron microscope (TEM) sample. For all samples, the strongest appeared in the out-of-plane direction of the diffraction peak, indicating that the polymer film was well organized in the shape of lamellar conjugated polymer stacks in a direction parallel to the axis of the substrate Structure. The distance between adjacent P3HT-azide polymers and the pi-pi laminar distance were 1.64 nm and 0.38 nm, respectively, consistent with the well-aligned P3HT-azide chains. The distance between the adjacent P3HT chains in the fibril structure P3HT-g-P2VP (2.0) was slightly increased to 1.83 nm while the higher integer peak (200) (400) was slightly different from that of the P3HT- . In contrast to P2VP as the molecular weight (M _{n, P2VP)} value increases, the distance between adjacent chains of the P3HT in P3HT-g-P2VP (4.4) and P3HT-g-P2VP (8.4) further increases as shown respectively 2.18nm and 2.24nm , The higher integer peak of the P3HT crystal was still clearly observed. These results indicate that the P3HT domain remains semicrystalline and that P3HT crystals are confined within their lamellar and cylinder domains. Since the crystallinity is inherently closely related to the electrical properties of polymer electronic devices, the above results are very important. The P3HT-g-P2VP higher integer peak of the spherical structure did not appear so prominently when compared to the case of the P3HT-azide because it strongly affects the spherical nanostructure of the curved interface It seems to be due to a highly confined and diminished chain structure.

Further, as another embodiment of the present invention, it is possible to form an active layer including a copolymer such as P3HT-g-P2VP and form an organic solar cell including the P3HT-g-P2VP. Or the like, and then a flexible display including the organic FET may be formed.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments described in the present invention are not intended to limit the technical spirit of the present invention but to illustrate the present invention. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents thereof should be construed as being included in the scope of the present invention.

400: P3HT-g-P2VP copolymer
410: P3HT-azide
420: P2VP-alkyne

Claims (14)

(a) preparing a predetermined polymer and a first polymer polymerized with an alkyl group-attached thioephene; And
(b) forming a grafted copolymer on said first polymer through a click reaction,
Here, the conjugate may be a second polymer that can be formed by chain growth polymerization, a polymer, or a luminescent monomolecule,
At this time, an azide group is introduced into the terminal of a part or the whole of the alkyl group,
An alkyne group is introduced at the end of the conjugate,
And the alkyne group reacts with the azide group to form a bonding structure. The method according to claim 1,
Wherein the number of carbon atoms contained in the alkyl group is in the range of 4 to 12. &lt; RTI ID = 0.0 &gt; 11. &lt; / RTI &gt; The method according to claim 1,
When the second polymer is used as the conjugate,
Wherein the interaction of the first polymer is controlled using the length or density of the second polymer. The method according to claim 1,
When the second polymer is used as the conjugate,
The second polymer may be one or a mixture of two or more of polystyrene, poly (2-vinylryridine), P4VP, poly (methyl methacrylate), polyactide, polybutadiene &Lt; / RTI &gt; The method according to claim 1,
In the step (b)
Wherein the first polymer and the conjugate are dissolved in a predetermined solvent to proceed a click reaction. 6. The method of claim 5,
Wherein one of tetrahydrofuran or chloroform is used as the solvent. The method according to claim 1,
In the step (b)
Characterized in that the copolymer is formed through a high frequency-assisted click reaction. The method according to claim 1,
The first polymer is P3HT (poly (3-hexylthiophene)),
The conjugate is P2VP,
Thereby forming a P3HT-g-P2VP copolymer in the step (b). 9. The method of claim 8,
Wherein the ordered structure is formed by setting the volume ratio of P3HT to the P3HT-g-P2VP copolymer to 60% or less. 9. The method of claim 8,
The volume ratio of P3HT to the P3HT-g-P2VP copolymer is,
Wherein the molecular weight of the P2VP is controlled through the molecular weight of the P2VP. A backbone comprising a first polymer polymerized with thioephene with an alkyl group attached thereto; And
And a conjugate that is grafted to some or all of the monomers of the first polymer,
Wherein the conjugate is a second polymer capable of being formed by chain growth polymerization, a polymer, or a luminescent monomolecule. 12. The method of claim 11,
The second polymer may be one or a mixture of two or more of polystyrene, poly (2-vinylryridine), P4VP, poly (methyl methacrylate), polyactide, polybutadiene . &Lt; / RTI &gt; 12. The method of claim 11,
The first polymer is P3HT (poly (3-hexylthiophene)),
The conjugate is P2VP,
The volume ratio of P3HT to the P3HT-g-P2VP copolymer thus formed is not more than 0.6,
Wherein the P3HT-g-P2VP copolymer has an ordered structure. A flexible display comprising an organic field effect transistor (organic FET) comprising the conjugated copolymer according to any one of claims 11 to 13.

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