KR100677795B1 - Method of Producing ?-Conjugated Polymers - Google Patents

Abstract

The present invention relates to a process for preparing a π-conjugated polymer comprising (1) complexing a monomer compound with a cyclodextrin, and (2) polymerizing the complexed compound with a chemical oxidant. The process of the present invention facilitates simple and rapid polymerization and reduces the discomfort caused by odors. Cyclodextrin complexes obtained as intermediate compounds are particularly useful for making through connected circuit boards and multilayer substrate structures.

Cyclodextrin complex, π-conjugated polymer, through-connected circuit board, multilayer board

Description

Method of producing π-conjugated polymers {Method of Producing π-Conjugated Polymers}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the production of π-conjugated polymers having high electrical conductivity by chemical oxidation of complexed monomer compounds, and to a process for producing circuit boards and multilayer substrates connected through.

π-conjugated polymer compounds have been a major problem in various publications in recent decades. These are also known as conductive polymers or synthetic metals.

Because of the highly delocalized π-electrons along the backbone, these polymers exhibit interesting (nonlinear) optical properties and become good electron conductors after oxidation or reduction. These compounds are therefore useful in a variety of practical applications, for example in data storage, optical signal processing, electromagnetic interference (EMI) suppression and solar energy conversion, and in rechargeable batteries, light emitting diodes, field effect transistors, circuit boards, sensors and antistatics. It will play a major and active role in matter.

Examples of known π-conjugated polymers are polypyrrole, polythiophene, polyaniline, polyacetylene, polyphenylene and poly (p-phenylene-vinylene). These can be prepared by various chemical and electrochemical polymerization methods [Stenger-Smith, J.D. Prog. Polym. Sci. 1998, 23, 57-79, Feast, W. J .; Tsibouklis, J .; Pouwer, K. L .; Groenendaal, L .; Meijer, E.W. Polymer 1996, 37, 5017-5047.

As an industrial production method of these (pi) -conjugated polymers, the chemical polymerization method of a monomer compound is the most favorable. There are several problems with this method:

1) The low solubility of monomeric compounds in water often means that it is necessary to use environmentally unfriendly organic solvents such as chloroform, methylene chloride or acetonitrile.

2) Many monomeric compounds produce unpleasant and harmful odors.

3) Pure or dissolved monomeric compounds are often unstable to air and / or light exposure, resulting in (partly) degradation.

Surprisingly, it has now been found that the above problems in the chemical polymerization of monomer compounds can be avoided by complexing the monomer compounds with cyclodextrins (CD).

The complexing of monomeric compounds with cyclodextrins and the subsequent electrochemical polymerization of the CD complexes are known. DeFeyter et al. Chem. Phys. Lett. 1997, 277, 44-50] studied α-terthiophene / γ-CD complexes using excited dimeric fluorescence in aqueous solution. Dong et al. [Chin. Chem. Lett. 1992, 3 (2), 129-132, polymerized aniline / α-CD complexes by electrochemical methods to rule out certain theories about by-products formed when electrochemically producing polyaniline. Lasace et al. Chem. Commun. 1998, 489; J. Chim. Phys. 1998, 95, 1208-1212 reported on the electrochemical polymerization of 2,2'-bithiophene / hydroxypropyl-β-CD complexes in water.

In addition, the same group recently reported on the electrochemical polymerization of many N, N-substituted dipyrrole derivatives complexed with hydroxypropyl-β-CD [J. Chim. Phys. 1998, 95, 1196-1199.

However, the possibility of chemical polymerization of monomer / CD complexes was not reported in any of the cited publications. Likewise, there have been no reports of using these complexes to stabilize monomeric compounds and noticeably reducing odors due to complex formation.

Therefore, the present invention

1. complexing a monomer compound with a cyclodextrin, and

2. Polymerizing the complexed compound with a chemical oxidant

It relates to a method for producing a π-conjugated polymer comprising at least.

Examples of monomeric compounds are unsubstituted or substituted pyrroles, anilines, thiophenes, vinyl and benzyl derivatives, or combinations of these compounds. Preference is given to using pyrrole and thiophene.

Pyrrole and 3,4-ethylenedioxythiophene (EDT) are particularly preferred as monomers.

Alkyl and alkoxy groups having 1 to 30 carbon atoms are suitable as substituents.

Suitable cyclodextrins for preparing monomer / cyclodextrin complexes are unsubstituted and substituted cyclodextrins.

Preferred cyclodextrins are α-, β- and γ-cyclodextrins and esters, alkyl ethers, hydroxyalkyl ethers, alkoxycarbonylalkyl ethers and their carboxyalkyl ether derivatives, or salts thereof.

Methyl-α-cyclodextrin, methyl-β-cyclodextrin, methyl-γ-cyclodextrin, ethyl-β-cyclodextrin, butyl-α-cyclodextrin, butyl-β-cyclodextrin, butyl-γ-cyclodextrin, 2 , 6-dimethyl-α-cyclodextrin, 2,6-dimethyl-β-cyclodextrin, 2,6-dimethyl-γ-cyclodextrin, 2,6-diethyl-β-cyclodextrin, 2,6-dibutyl -β-cyclodextrin, 2,3,6-trimethyl-α-cyclodextrin, 2,3,6-trimethyl-β-cyclodextrin, 2,3,6-trimethyl-γ-cyclodextrin, 2,3,6 -Trioctyl-α-cyclodextrin, 2,3,6-trioctyl-β-cyclodextrin, 2,3,6-triacetyl-α-cyclodextrin, 2,3,6-triacetyl-β-cyclodextrin , 2,3,6-triacetyl-γ-cyclodextrin, (2-hydroxy) propyl-α-cyclodextrin, (2-hydroxy) propyl-β-cyclodextrin, (2-hydroxy) propyl-γ Cyclodextrins, partially or fully acetylated and matured Particular preference is given to cynylated α-, β- or γ-cyclodextrin, 2,6-dimethyl-3-acetyl-β-cyclodextrin and 2,6-dibutyl-3-acetyl-β-cyclodextrin.

Mono-, di- or triether, mono-, di- or triester or monoester / diester substituted derivatives are generally alkylating agents, for example dimethyl sulfate or alkyl halides having 1 to 30 carbon atoms, for example chloride, Etherify α-, β- and γ-cyclodextrin with methyl bromide or methyl iodide, ethyl, propyl, butyl, pentyl, hexyl, heptyl or octyl and / or esterification with acetic acid or succinic acid in the presence of acid Get by.

Examples of suitable oxidizing agents include Fe (III) salts, in particular FeCl ₃ , H ₂ O ₂ , K ₂ Cr ₂ O ₇ , K ₂ S ₂ O ₈ , Na ₂ S ₂ O ₈ , KMnO ₄ , alkali metal perborates and Alkali metal or ammonium persulfate. More suitable oxidizing agents are described, for example, in Handbook of Conducting Polymers (Ed. Skotheim, TA), Marcel Dekker: New York, 1986, Vol. 1, 46-57.

Methods of preparing monomeric compounds are generally well known and described, for example, in Handbook of Conducting Polymers (Ed. Skotheim, T.A.), Marcel Dekker: New York, 1986, Vol. 1, 1-43; Feast, W. J .; Tsibouklis, J .; Pouwer, K. L .; Groenendaal, L .; Meijer, E. W., Polymer 1996, 37, 5017-5047, and G. Heywang; F. Jonas, Adv. Mater. 1992, 4, 116-118.

Methods of making cyclodextrins are also known and described, for example, in "Roempp Lexikon Chemie" (Roempp's Lexicon of Chemistry), 10th edition, Stuttgart / New York, 1997, pp. 845, and Chemical Reviews 98 (1998) 1743-1753 and 1919-1958.

In a preferred embodiment of the present invention, the complexing of the monomer compound is carried out with a molar ratio of monomer / cyclodextrin of 1: 1-1.2.

The above problems can be avoided by the method according to the invention. Depending on the type of cyclodextrin, more water soluble or less water soluble complexes can be prepared, which have the following advantages.

1) Using more than 1 molar equivalent of cyclodextrin rapidly increases the water solubility of the monomer (for example, by using 2,6-dimethyl-β-cyclodextrin, the water solubility of 3,4-ethylenedioxythiophene is 30 times or more). May increase). This allows chemical polymerization in water to be carried out even at much higher monomer concentrations.

2) When more than 1 molar equivalent of cyclodextrin is used, the vapor pressure is drastically reduced, and the monomer odor disappears.

3) In the cyclodextrin-complexed form of the monomer, the monomer does not discolor upon exposure to air and light. This applies to both water soluble complexes and pure solid phase complexes.

It is noteworthy that the complex can be easily separated into individual compounds by using organic solvents or heat. This allows the complex to store and / or transport sensitive monomers, which is very interesting. In addition, monomer / cyclodextrin complexes can be easily characterized by methods such as, for example, UV spectroscopy, fluorescence spectroscopy, infrared spectroscopy, NMR spectroscopy, mass spectrometry, cyclic voltammetry, and in some cases, X-ray structure analysis. .

In addition to using chemical oxidants, the complex may be electrochemically polymerized.

Electrochemical polymerization can be carried out using conventional electrochemical apparatus, for example in an aqueous solution of LiClO ₄ as electrolyte.

A particularly important field of application of the π-conjugated polymers produced by the process according to the invention is for example:

-Data storage,

Optical signal processing,

-Electromagnetic interference (EMI) suppression,

-Solar energy conversion,

-Rechargeable battery,

-Light emitting diodes,

-Field effect transistors,

- sensor,

Antistatic materials, and

Through connection of circuit boards and multilayer boards.

Cyclodextrin complexes are particularly beneficial for the protection of sensitive monomeric compounds because of their high solubility.

Another advantage is that the cyclodextrin can be reused after polymerizing the complexed monomers.

A particularly important possible use of cyclotextine complexes is to use them in the penetration connection of circuit boards and multilayer boards.

Two-layer and multilayer circuit boards have a number of perforated holes that must be metalized in order to be able to receive current from the first conductor track level to the second level and to connect conventional electrical components to the circuit board in a conductive manner. Initially no current flows through the perforated holes, providing a thin layer of copper (2-3 μm) in the chemical copper bath for through connection.

Recently, it has become important to deposit copper directly on the perforated hole walls in the circuit board without electrochemical copper bath. For this purpose, it is necessary to provide a perforated hole wall with an electrically conductive coating before depositing copper by electroplating. In order for this coating to serve as a basis for depositing copper on the entire surface without defects by electroplating, it must be applied evenly and have sufficient electrical conductivity (through connection).

Cyclodextrin complexes known to the present invention can be readily and quickly polymerized directly on a circuit board.

Thus, the present invention is also characterized in that a conductive layer of π-conjugated polymer is formed on the perforated hole wall by treatment with a cyclodextrin complex solution or emulsion of monomeric compounds, and the metal is deposited on this layer by electroplating. A method of manufacturing a connected circuit board and a multilayer board.

Compared to the methods described in, for example, US Pat. No. 5,194,313, the use of cyclodextrin complexes prevents contamination by monomer evaporation, especially when using low boiling monomer compounds.

Preference is given to using cyclodextrin complexes of unsubstituted or substituted pyrrole or thiophene derivatives.

It is also particularly preferred to use pyrrole or cyclodextrin complexes of 3,4-ethylene-dioxythiophene.

The method according to the invention comprises the following steps:

1.Step of manufacturing perforated holes in copper laminate (substrate)

2. pretreatment of the drilled hole by oxidation

3. Rinse with water

4. treating with a cyclodextrin complex solution or emulsion of monomeric compounds

5. The step of treating with acid

6. Rinse with water

7. Depositing Copper by Electroplating

Manufacturing steps 4 and 5 can be combined in a single step. This embodiment is preferred. Steps 1, 2, 3, 6 and 7 correspond to the prior art and are carried out in a manner known to date. In step 2, it is preferable to use potassium permanganate as the oxidizing agent.

The cyclodextrin complex may be used in preparation step 4 at a concentration of 1 to 60% by weight, preferably 10 to 50% by weight, based on the total solution or emulsion.

Further details of the preparation, in particular information on the type of acid, solvent and other auxiliaries used, are known and described in European Patent Application Publication No. 553 671.

In the examples below, methylated β-cyclodextrins with an average degree of methylation per glucose unit of 1.8 were used.                 

Example 1

Preparation of EDT / cyclodextrin Complexes:

To an aqueous solution of 2,6-dimethyl-β-cyclodextrin (600 g (0.45 mol) dissolved in 1 L of water) 64 g (0.45 mol) of EDT were added. After a few minutes, a clear solution was obtained. Complex formation can be facilitated by ultrasonic or flask shaking.

The EDT / cyclodextrin complex is very stable and substantially protected from oxidation. No discoloration was observed even after standing in the air.

Preparation of pyrrole / cyclodextrin complexes:

30.22 g (0.45 mol) of pyrrole was added to an aqueous solution of 2,6-dimethyl-β-cyclodextrin (600 g (0.45 mol) dissolved in 1 L of water). After a few minutes, a clear solution was obtained. Complex formation can be facilitated by ultrasonic or flask shaking.

The pyrrole / cyclodextrin complex is very stable and substantially protected from oxidation. No discoloration was observed even after standing in the air.

The table below shows the different properties of the pyrrole and EDT and the corresponding cyclodextrin complexes. The cyclodextrin used was in each case 2,6-dimethyl-β-cyclodextrin.

Monomer Monomer / CD complex (molar ratio 1: 1.05) Solubility (in water at 20 ℃) Pyrrole: 50 g / l EDT: 2.1 g / l Pyrrole:> 100 g / l EDT:> 80 g / l smell Pyrrole: very strong and offensive EDT: very strong and offensive In aqueous solution: pyrrole: slight odor EDT: slight odor Solid phase: pyrrole: slight odor EDT: slight odor stability Pyrrole: Discoloration in the air after only a few hours EDT: Discoloration in the air after only a few hours In aqueous solution: pyrrole: no discoloration EDT: no discoloration Solid state: pyrrole: no discoloration EDT: no discoloration

Example 2

Preparation of EDT / cyclodextrin Complexes and Subsequent Chemical Oxidation Polymerization

a) 10 g (7.5 mmol) of 2,6-dimethyl-β-cyclodextrin was dissolved in 30 mL of H ₂ O. To this solution was added 1.065 g (7.5 mmol) of 3,4-ethylenedioxythiophene (EDT). The solution was stirred vigorously (about 10 minutes) or treated with an ultrasonic device (10 seconds) to obtain a clear homogeneous solution. The formation of the complex compound is either NMR (0.2 ppm shift of ¹ H-NMR in D ₂ O) or fluorescence spectroscopy (a rapid increase in fluorescence intensity of EDT in H ₂ O due to addition of 2,6-dimethyl-βcyclodextrin) It can be explained.

b) 5.0685 g (18.75 mmol) of FeCl ₃ x 6 H ₂ O was added to the solution prepared in a) and the mixture was stirred at 70 ° C. After 12 hours, the resulting poly (ethylenedioxythiophene) was suction filtered through a membrane filter (5 μm). The filter residue is resuspended twice in 50 ml of hot water and suction filtered; Subsequently, it was resuspended in 50 ml of methanol, filtered by suction and dried at 60 ° C. for 5 hours in a vacuum drying oven.

Yield: 0.9 g

Example 3

Preparation of Pyrrole / Cyclodextrin Complexes and Subsequent Chemical Oxidation Polymerization

a) 10 g (7.5 mmol) of 2,6-dimethyl-β-cyclodextrin was dissolved in 30 mL of H ₂ O. 0.5 g (7.5 mmol) of pyrrole was added to this solution. This solution was vigorously stirred (about 1 minute) to obtain a clear homogeneous solution. The formation of the complex compound can be explained by ¹ H-NMR or fluorescence spectroscopy.

b) 2.53 g (9.38 mmol) of K ₂ S ₂ O ₈ were added to the solution prepared in a) and the mixture was stirred at 30 ° C. After reacting for 6 hours, the resulting polypyrrole was suction filtered through a membrane filter (5 μm). The filter residue is resuspended twice in 50 ml of hot water and suction filtered; Subsequently, it was resuspended in 50 ml of methanol and dried at 60 ° C. for 5 hours in a vacuum drying oven.

Yield: 0.45 g

Example 4

Through connection:

A 4 x 4 cm 2 epoxy resin substrate with 20 perforated holes, each laminated with copper on each side and 0.4 mm in diameter, was immersed in a solution of 6.5 g of potassium permanganate, 1 g of boric acid, and 92.5 g of water at 85 ° C. for 4 minutes. It was. Subsequently, the substrate was washed with demineralized water until the water flowing out became colorless.

The substrate was immersed in a solution of 3 g of pyrrole and 97 g of water for 2 minutes (plate A, solution A).

A second substrate was immersed for 2 minutes in a solution of 3 g of pyrrole, 65.5 g of 2,6-dimethyl-β-cyclodextrin and 97 g of water (plate B, solution B).

The second substrate was then immersed in an aqueous 2% by weight polystyrenesulfonic acid solution for 2 minutes and subsequently washed with water. The perforated holes of substrates A and B were completely coated with polypyrrole. Then, in copper plating, the substrate was plated with copper in a commercially available acidic copper bath.

The perforated holes of the two substrates were completely plated with copper.

The advantages according to the invention with solution B over solution A are illustrated by the following test:

In each case 100 ml of solutions A and B were introduced into a 2 L measuring cylinder. A piece of filter paper moistened with an aqueous solution of iron (III) chloride at a concentration of 5% by weight was floated in the solution and the measuring cylinder was sealed with a rubber stopper. In solution A, the piece of filter paper became black after about 10 seconds due to the formation of polypyrrole, but in solution B, discoloration was not observed even after 2 minutes.

This example shows that by the process according to the invention unwanted evaporative losses can be avoided in practice.

Claims (9)

1. complexing a monomer compound which is pyrrole or 3,4-ethylenedioxythiophene with cyclodextrin, and 2. Polymerizing the complexed compound with a chemical oxidant A method for producing a π-conjugated polymer comprising at least. delete delete The cyclodextrin used according to claim 1, wherein the cyclodextrin used is methyl-α-cyclodextrin, methyl-β-cyclodextrin, methyl-γ-cyclodextrin, ethyl-β-cyclodextrin, butyl-α-cyclodextrin, butyl-β- Cyclodextrin, butyl-γ-cyclodextrin, 2,6-dimethyl-α-cyclodextrin, 2,6-dimethyl-β-cyclodextrin, 2,6-dimethyl-γ-cyclodextrin, 2,6-diethyl- β-cyclodextrin, 2,6-dibutyl-β-cyclodextrin, 2,3,6-trimethyl-α-cyclodextrin, 2,3,6-trimethyl-β-cyclodextrin, 2,3,6-trimethyl -γ-cyclodextrin, 2,3,6-trioctyl-α-cyclodextrin, 2,3,6-trioctyl-β-cyclodextrin, 2,3,6-triacetyl-α-cyclodextrin, 2, 3,6-triacetyl-β-cyclodextrin, 2,3,6-triacetyl-γ-cyclodextrin, (2-hydroxy) propyl-α-cyclodextrin, (2-hydroxy) propyl-β-cyclo Dextrin, (2-hydroxy) propyl-γ-cycle Rodextrin, partially or fully acetylated and succinylated α-, β- or γ-cyclodextrin, 2,6-dimethyl-3-acetyl-β-cyclodextrin and 2,6-dibutyl-3-acetyl- β-cyclodextrin. Treatment with a cyclodextrin complex solution or emulsion of monomeric compounds to form a conductive layer of π-conjugated polymer in the perforated hole wall, subsequently or simultaneously treated with an acid, and depositing a metal on this layer by electroplating. The manufacturing method of the circuit board and the multilayer board | substrate connected through. 6. The method of claim 5, wherein a cyclodextrin complex of unsubstituted or substituted pyrrole or thiophene derivatives is used. 6. The process according to claim 5, wherein pyrrole or a cyclodextrin complex of 3,4-ethylenedioxythiophene is used. The method of claim 5, 1.Step of manufacturing perforated holes in copper laminated substrate (substrate) 2. pretreatment of the drilled hole by oxidation 3. Rinse with water 4. treating with a cyclodextrin complex solution or emulsion of monomeric compounds 5. The step of treating with acid 6. Rinse with water 7. Depositing Copper by Electroplating Method comprising a. The method of claim 8, wherein manufacturing step 4 and step 5 are combined.