Production of polyaniline graphitic carbon nitride nanocomposites with high electrical conductivity

Abstract

A method for producing nano-composites comprising graphitic carbon nitride reduced to nano size, having high electrical conductivity is provided. The method includes the steps of: producing graphitic carbon nitride (g-C.sub.3N.sub.4) having a chemical formula (C.sub.3N.sub.4).sub.m, applying an obtained g-C.sub.3N.sub.4 powder via an ultrasonic homogenization method on concentrations, obtaining a nano g-C.sub.3N.sub.4 suspension, wherein a size of the nano g-C.sub.3N.sub.4 suspension changes between 10-100 nm as a result of applying the ultrasonic homogenization method, obtaining polyaniline with a chemical formula (C.sub.6H.sub.7N).sub.n in an emeraldine salt form, obtaining a nano-composite, mixing in aniline or aniline-HCl water at concentrations of 0.1-1 mol/L, adding a nano graphitic carbon (nano g-C.sub.3N.sub.4) into a mixture and mixing between 10-60 minutes, carrying out a polymerization process by adding an oxidant to the mixture and obtaining the nano composite having the high electrical conductivity.

Claims

1. A production method for a nano-composite with a high electrical conductivity, comprising the steps of: producing graphitic carbon nitride (g-C.sub.3N.sub.4) comprising a chemical formula (C.sub.3N.sub.4).sub.m (Formula-I), by a thermal polymerization method at a temperature between 450 and 600° C., ##STR00003## applying an obtained g-C.sub.3N.sub.4 powder via an ultrasonic homogenization method on concentrations, wherein the concentrations vary between 1 and 20% in mass for 10-60 minutes at a temperature of 4-25° C., obtaining a nano g-C.sub.3N.sub.4 suspension, wherein a size of the nano g-C.sub.3N.sub.4 suspension changes between 10-100 nm as a result of applying the ultrasonic homogenization method, obtaining polyaniline with a chemical formula (C.sub.6H.sub.7N).sub.n (Formula-II) in an emeraldine salt form using a first oxidant at room temperature from 99% pure aniline or aniline hydrochloride monomers, having a monomer concentration value between 0.1 to 1 mol/L, ##STR00004## obtaining a nano-composite by mixing the polyaniline in the emeraldine salt form with the nano g-C.sub.3N.sub.4 suspension, or mixing in aniline or aniline-HCl water at concentrations of 0.1-1 mol/L to obtain a mixture, adding a nano graphitic carbon nitride (nano g-C.sub.3N.sub.4) into the mixture and mixing between 10-60 minutes, carrying out a polymerization process by adding a second oxidant to the mixture and obtaining the nano-composite with the high electrical conductivity.

2. The production method according to claim 1, wherein the first oxidant is one selected from iron (III) chloride, ammonium persulphate, potassium persulphate or sodium persulphate, and a monomer/oxidant ratio is: 1/1, 1/3, 1/5, in order to obtain the polyaniline in the emeraldine salt form.

3. The production method according to claim 2, comprising the step of carrying out a purification process by washing the nano-composite with a 0.1M hydrochloric acid solution and acetone.

4. The production method according to claim 2, comprising the step of adding the nano graphitic carbon nitride into the mixture comprising the aniline or aniline-HCl water to enable a polyaniline/nano g-C.sub.3N.sub.4 ratio is 2/1, 3/1, 5/1, 10/1.

5. The production method according to claim 1, comprising the step of carrying out a purification process by washing the nano-composite with a 0.1M hydrochloric acid solution and acetone.

6. The production method according to claim 5, comprising the step of adding the nano graphitic carbon nitride into the mixture comprising the aniline or aniline-HCl water to enable a polyaniline/nano g-C.sub.3N.sub.4 ratio is 2/1, 3/1, 5/1, 10/1.

7. The production method according to claim 1, comprising the step of adding the nano graphitic carbon nitride into the mixture comprising the aniline or aniline-HCl water to enable a polyaniline/nano g-C.sub.3N.sub.4 ratio is 2/1, 3/1, 5/1, 10/1.

Description

DETAILED DESCRIPTION OF THE EMBODIMENTS

(1) The invention is a nano-composite production method having high electrical conductivity comprising the steps of; producing graphitic carbon nitride (g-C.sub.3N.sub.4) having the chemical formula (C.sub.3N.sub.4).sub.m (Formula I), by means of a thermal polymerization method at temperatures between 450 and 600° C.,

(2) ##STR00001## applying the obtained g-C.sub.3N.sub.4 powder via an ultrasonic homogenization method on concentrations that vary between 1 and 20% in mass for 10-60 minutes at temperatures of 4-25° C., obtaining nano g-C.sub.3N.sub.4 suspension whose size changes between 10-100 nm as a result of applying the ultrasonic homogenization method, obtaining polyaniline with the chemical formula (C.sub.6H.sub.7N).sub.n (Formula II) in emeraldine salt form using oxidants at room temperature from 99% pure aniline or aniline hydrochloride monomers, having a monomer concentration value between 0.1 to 1 mol/L,

(3) ##STR00002## obtaining nano-composite by mixing the obtained polyaniline in emeraldine salt form with nano g-C.sub.3N.sub.4 suspension, or mixing in aniline or aniline-HCl water at concentrations of 0.1-1 mol/L, adding nano graphitic carbon (nano g-C.sub.3N.sub.4) into the mixture and mixing between 10-60 minutes, carrying out a polymerization process by adding oxidant to the mixture and obtaining nano composite having high conductivity carrying out purification process by washing the obtained composite with 0.1M hydrochloric acid solution and acetone.

(4) In the developed method, first of all g-C.sub.3N.sub.4 is produced from urea at temperatures between 450 and 600° C. by means of the thermal polymerization method (Lyu et al. 2011). Nano g-C.sub.3N.sub.4 suspension whose size changes between 10-100 nm is obtained following this process, by applying the ultrasonic homogenization method for 10-30 minutes at 4° C.'s to the 1% by mass of aqueous solution of the powder that has been produced.

(5) Following this polyaniline in emeraldine salt form is synthesized by using various oxidants (iron (III) chloride, ammonium persulphate, potassium persulphate, sodium persulphate) at different mol ratios (monomer/oxidant ratio 1/1, 1/3, 1/5) at room temperature such that the monomer concentration obtained from 99% pure aniline or aniline hydrochloride monomers is 0.2 mol/L.

(6) Finally, nano-composites are obtained by synthesizing the synthesized polyaniline in the presence nano g-C.sub.3N.sub.4 (in situ) or by synthesizing polyaniline and g-C.sub.3N.sub.4 separately and mixing them together (ex situ).

(7) In the case of synthesizing polyaniline in the presence of nano g-C.sub.3N.sub.4 (in situ), first of all aniline or aniline-HCl is mixed in water at concentrations of 0.1-1 mol/L. Following this, nano graphitic carbon nitride is added to the solution such that the polyaniline/nano g-C.sub.3N.sub.4 o ratios are 2/1, 3/1, 5/1, 10/1 and this is mixed further for 10-60 minutes. Afterwards, iron (III) chloride, ammonium persulphate, potassium persulphate or sodium persulphate that is used as an oxidant is added to the solution such that the monomer/oxidant ratio is: 1/1, 1/3, 1/5 and the solution is mixed for 6-16 hours. As a result emeraldine form is obtained which is a conductive salt of polyaniline [formula: (C.sub.6H.sub.7N).sub.n. The composite that is obtained is washed with 0.1M hydrochloric acid solution and acetone and the purification process is carried out.

(8) Nano-composites are prepared by polymerization or by applying different aniline/nano g-C.sub.3N.sub.4 ratios (polyaniline/nano g-C.sub.3N.sub.4 ratios (2/1, 3/1, 5/1, 10/1)). While nano-composites having a polyaniline/nano g-C.sub.3N.sub.4 ratio of 10/1 from the produced nano-composites exhibited the highest conductivity (3500 S/cm), it was noted that as the polyaniline ratio decreased conductivity was reduced. The lowest conductivity value was measured as 600 S/cm in nano-composites that had polyaniline/g-C.sub.3N.sub.4 ratio of 2/1. The conductivity of other nano-composites has been measured within this range.

(9) The composite obtained after these process steps is formed of dark green coloured polyaniline that is a conductive polymer and graphitic carbon nitride in white powder form that is used as an additive. The physical state of the composite is in dark green powder form. It is moulded under pressure to establish a conductive tablet. Its conductivity feature is basically obtained from polyaniline and is supported with graphitic carbon nitride that exhibits semi-conductive properties.

REFERENCES

(10) 1. Zuo, Shixiang, Yao Chen, Wenjie Liu, Chao Yao, Yingruo Li, Jiangquan Ma, Yong Kong, Huihui Mao, Zhongyu Li, and Yongsheng Fu. 2017. ‘Polyaniline/gC 3 N 4 composites as novel media for anticorrosion coatings’, Journal of Coatings Technology and Research, 14: 1307-14. 2. Bahuguna, Ashish, Priyanka Choudhary, Tripti Chhabra, and Venkata Krishnan. 2018. ‘Ammonia-Doped Polyaniline-Graphitic Carbon Nitride Nanocomposite as a Heterogeneous Green Catalyst for Synthesis of Indole-Substituted 4H-Chromenes’, ACS Omega, 3: 12163-78. 3. Lyu, Jing, et al. “Electromagnetic interference shielding based on a high strength polyaniline-aramid nanocomposite.” Composites Science and Technology 149 (2017): 159-165. APA