KR20030037053A - Preparation of polypyrrole nanoparticles using low temperature microemulsion polymerization - Google Patents

Abstract

PURPOSE: Provided is a method for preparing polypyrrole nanoparticles, which produce nanoparticle of polypyrrole having substantially smaller size than that of nanoparticle obtained by existing emulsion polymerization. CONSTITUTION: The method comprises the steps of (i) dissolving a cationic surfactant of 1-40 deg.C into distilled water to form a micelle, (ii) slowly dropping a pyrrole monomer to the micelle, (iii) adding an iron trichloride dissolved into distilled water to the micelle, so as to react the reactants, and (iv) adding methanol and iso-octane to the reactants, and then isolating a nanoparticle layer. The cationic surfactant is selected from octyl trimethylammonium bromide, decyltrimethylammonium bromide, and dodecyltrimethylammonium bromide.

Description

Preparation method of polypyrrole of several nanometers size using low temperature microemulsion polymerization {Preparation of polypyrrole nanoparticles using low temperature microemulsion polymerization}

The present invention relates to a process for producing polypyrrole of several nanometers in size using low temperature microemulsion polymerization.

Nanoparticles are generally particles of the order of 1 to 100 nanometers in size and can be said to be the material between the molecules and the bulk solids. In the nanoparticle state, new electronic, magnetic, optical and electrical properties are found that are not seen in the molecular state or in the solid state. This new property is called the quantum size effect, which is why nanoparticles are often called quantum dots.

Recently, many methods of synthesizing nanoparticles using metals, metal oxides, or semiconductor materials have been studied because they are not only for academic interest in quantum size effects depending on size, but also for the purpose of developing various new materials using new properties. to be. As a result, a number of methods for producing metal and inorganic semiconductor nanoparticles of 1 nanometer or more have been published, and industrial applications have been actively studied. However, no method for preparing polymeric nanoparticles of 5 nanometers or less is known to date ( Curr. Opin. Colloid Interface Sci. , Vol 4, pp 6-14, 1999). The polymer nanoparticles synthesized up to now are mainly dozens to hundreds of nanometers in size, and due to their relatively large particle size, their application range has been limited compared to metal and inorganic semiconductor nanoparticles.

The inventors have succeeded for the first time to develop a method for producing polypyrrole nanoparticles of 5 nanometers or less.

In order to solve the conventional problems, it is an object to provide a method for producing polypyrrole nanoparticles of several nanometers or less.

Cationic surfactants such as octyltrimethylammonium bromide (OTAB), decyltrimethylammonium bromide (DeTAB), and dodecyltrimethylammonium bromide (DTAB) are dissolved in distilled water to form micelles, and the micelle inner space is prepared for nanoparticles. Used as a nano reactor. A certain amount of surfactant was added to distilled water adjusted to about 1-40 ° C. to stir to form micelles in solution. Pyrrole, a conductive polymer monomer, was continuously added while slowly dropping a certain amount. The molar ratio of iron trichloride (FeCl 3), an oxidizing agent, was adjusted and dissolved in a small amount of distilled water, and then added to the reaction solution. The reaction was continued at low temperature while stirring the reaction vessel for 1 to 12 hours. Excess methanol was added to the reaction vessel to dissolve and oxidize the surfactant and dissolve the remaining iron trichloride. The nanoparticles formed in the micelles were transferred to a separatory funnel to separate, and then a certain amount of isooctane was added to increase the separation rate. After the nanoparticle layer was completely separated, the methanol and isooctane solution of the upper layer was removed and the nanoparticle layer was naturally evaporated at room temperature to obtain pure nanoparticles.

(Example)

For example, the following examples will be described in detail. However, it is obvious that this embodiment does not limit the scope of the present application.

Example 1

Preparation of 2 nanometer polypyrrole nanoparticles

Using a thermostat, 5 grams of dodecyltrimethylammonium bromide (DTAB) was added to a reactor containing 80 milliliters of distilled water at 3 ° C. and stirred to form micelles. 2 grams of pyrrole monomer was slowly added dropwise using a pipette. 11.12 grams of iron trichloride (pyrrole / iron trichloride mole ratio = 1 / 2.3) was dissolved in 10 milliliters of distilled water and then added to the reaction vessel. After the reaction was stirred at 3 ° C. for 5 hours, 500 milliliters of methanol was added to the reactor. This was to wash off the remaining iron trichloride after reacting with the surfactant. The reaction solution was transferred to a separatory funnel and gently shaken several times to help mix the solution. To increase the separation rate of nanoparticles, 100 milliliters of non-solvent isooctane was added. In order to recover the precipitated polypyrrole nanoparticles, isooctane and methanol upper layers were removed using a pipette. The remaining polypyrrole nanoparticle layer was naturally evaporated at room temperature to obtain polypyrrole nanoparticles.

As a result of analyzing the prepared polypyrrole nanoparticles using a transmission electron microscope (TEM), it was confirmed that the polypyrrole particles of about 2 nanometers were obtained. And it was confirmed that the surfactant was removed from the polypyrrole nanoparticles obtained through nuclear magnetic resonance (NMR).

Example 2

In Example 1, it implemented similarly to Example 1 except having replaced with 21 degreeC instead of 3 degreeC in "~ set to 3 degreeC using a thermostat."

Example 3

In Example 1, it implemented similarly to Example 1 except having replaced with 40 degreeC instead of 3 degreeC in "~ set to 3 degreeC using a thermostat."

In low temperature microemulsion polymerization, the activity of surfactant is decreased so that the volume in micelle pores is reduced, and it is effective to obtain polypyrrole nanoparticles of significantly smaller size than nanoparticles obtained in conventional emulsion polymerization by using these pores as nanoreactors. have.

Claims (2)

Dissolving the cationic surfactant at 1 to 40 ° C. in distilled water to form micelles, Slowly dropwise adding pyrrole monomer thereto; Reacting by adding iron trichloride dissolved in distilled water, A method of preparing polypyrrole having a nanometer size of polypyrrole using low temperature microemulsion polymerization, characterized in that the step of adding methanol and isooctane and then separating the nanoparticle layer. The method of claim 1, A method of producing polypyrrole of several nanometers size using low temperature microemulsion polymerization, characterized in that the cationic surfactant is alternatively made of octyltrimethylammonium bromine, decyltrimethylammonium bromine, dodecyltrimethylammonium bromine.