The effect of synthesis media on the properties of substituted polyaniline/chitosan composites

doi:10.1016/j.carres.2011.06.009

Carbohydrate Research

Volume 346, Issue 14, 18 October 2011, Pages 2063-2069

https://doi.org/10.1016/j.carres.2011.06.009 Get rights and content

Abstract

Substituted polyaniline/chitosan (sPANI/Ch) composites were chemically synthesized in H₂SO₄ and CH₃COOH synthesis media. Structural and physical properties of the composites were characterized by using FTIR, SEM, TGA, UV–vis, XRD techniques, and conductivity measurements. The effect of synthesis media on morphology, thermal stability, conductivity, and crystalline properties was investigated. Chemical interactions between substituted polyanilines and chitosan were explained using FTIR spectra results. The different morphological surfaces were observed in SEM images of the composites. The size of the substituted polyaniline/chitosan (sPANI/Ch) composites was in nanoscale, and the composites synthesized in acetic acid media showed smaller structures than those of H₂SO₄ media and pure chitosan. It was interpreted from XRD results that the composites have amorphous structure and the PNEANI/Ch–CH₃COOH composite has the highest crystallinity.

Graphical abstract

Introduction

Intrinsically conducting polymers, such as polyaniline, polythiophene, or polypyrrole are used in scientific and industrial studies and in various applications, such as rechargeable batteries,¹ sensors,2, 3 and photovoltaics.⁴ Polyaniline (PANI), among the other conjugated polymers, has been attracting attention due to its high conductivity in the doped state, its environmental, thermal, and electrochemical stability, and its interesting electrochemical, electronic, optical, and electro-optical properties. However, a major problem in its successful utilization is its poor mechanical properties and processability due to its insoluble nature in common organic solvents. Incorporation of polar functional groups or long and flexible alkyl chains in the polymer backbone is a common technique to prepare polyaniline type polymers, which are soluble in water and/or organic solvents. For example, substituted polyanilines like polytoluidines, polyanisidines, poly(N-methylanilines), and poly(N-ethylanilines) are more soluble in common organic solvents than the unsubstituted polyaniline but less conductive.⁵

In considering biomedical applications of polyaniline and polyaniline derivative composites and blends, their polymer matrices should be biocompatible and biodegradable. Therefore, only limited polymers from synthetic or natural sources are available. Naturally occurring biopolymers, chitosan has received attention. Chitosan is the N-deacetylated derivative of chitin, a natural polysaccharide widely found in crustaceans and insects.⁶ It is widely used in wastewater treatments,⁷ separation membranes,8, 9 drug delivery systems,¹⁰ and biosensors11, 12 due to its biodegradability and structural properties.

In recent years, some works have been reported on the synthesis of PANI/chitosan, composites and blends.2, 13, 14, 15, 16, 17, 18, 19, 20, 21 Our group presented the synthesis of substituted polyaniline/chitosan composites in HCl acid medium.³ However, there is no reported detail study on the substituted polyaniline/chitosan composites synthesized in acetic and sulfuric acids. Moreover, there are few studies using XRD to investigate structural properties of PANI/Ch composites.

In this present work, we chemically synthesized substituted polyaniline/chitosan composites, such as poly(N-methylaniline)/chitosan (PNMANI/Ch), poly(N-ethylaniline)/chitosan (PNEANI/Ch), poly(2-ethylaniline)/chitosan (P2EANI/Ch) in acetic and sulfuric acids. FTIR and UV–vis spectroscopies, TGA and SEM analyses were used to characterize the composites. The crystallinity of each composite was investigated by XRD. The electrical conductivity measurements of composites were made using a four-point probe technique. This work is focused also to explain the relationship between crystallinity and conductivity of the composites. The properties of the composites are compared with those of a polyaniline/chitosan (PANI/Ch) composite, synthesized with the same conditions.

Section snippets

Materials

Aniline(ANI), N-methylaniline (NMANI), N-ethylaniline (NEANI), 2-ethylaniline (2EANI) were obtained from Aldrich, and the monomers were under nitrogen prior to use. Chitosan with medium molecular weight was also purchased from Aldrich. Ammonium peroxydisulfate, sulfuric acid, acetic acid, and N-methyl-2-pyrrolidone (NMP) (Fluka) were used as received.

Synthesis of substituted polyaniline/chitosan composites

The substituted polyaniline/chitosan composites (sPANI/Ch) were synthesized in CH₃COOH and H₂SO₄ media. An aqueous solution of chitosan (0.2 g) was

FTIR results

FTIR spectra were used to determine the chemical structure of the substituted polyaniline/chitosan composites in two different acid solutions, as shown in Figure 1a, Figure 1b. For sPANI/Chitosan composites, the characteristic peaks (Table 1) between 1564–1588, 1490–1502, 1265–1309, 1100–1108, and 799–817 cm⁻¹ in CH₃COOH and 1560–1607, 1474–1497, 1156–1306, 1077–1097, and 789–814 cm⁻¹ in H₂SO₄ were attributed, respectively, to C double bond C stretching of the quinoid ring (Q, representing the quinoid ring), C

Conclusions

We have successfully synthesized and characterized sPANI/Ch composites synthesized in sulfuric and acetic acid media. From the SEM analysis, it was observed that each composite has a different mophological structure. Degree of crystallinity of sPANI/Ch–CH₃COOH is higher than that of sPANI/Ch–H₂SO₄. The crystallinity was greatly enhanced from intra- and intermolecular interactions, that are, explained by hydrogen bonding. Spectroscopic, morphological, thermal, and electrical conductivity

References (32)

B.-L. He et al.
Mater. Chem. Phys.
(2009)
R. Khan et al.
Biosens. Bioelectron.
(2009)
A.G. Yavuz et al.
Carbohydr. Polym.
(2009)
A. Kapil et al.
Synth. Met.
(2009)
B. Li et al.
Carbohydr. Polym.
(2008)
P. Baroni et al.
J. Hazard. Mater.
(2008)
A.G. Yavuz et al.
Carbohydr. Polym.
(2010)
X. Kang et al.
Biosens. Bioelectron.
(2009)
Y.A. Ismail et al.
Sens. Actuator, B Chem.
(2008)
S.R. Shin et al.
Synth. Met.
(2005)

T. Thanpitcha et al.

Carbohydr. Polym.

(2006)

G.M. Spinks et al.

Sens. Actuator, B Chem.

(2007)

A. Tiwari et al.

Talanta

(2009)

A.G. Yavuz et al.

Synth. Met.

(2007)

A.T. Ramaprasad et al.

Synth. Met.

(2009)

J.H. Sung et al.

Mater. Chem. Phys.

(2003)

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The effect of synthesis media on the properties of substituted polyaniline/chitosan composites

Abstract

Graphical abstract

Introduction

Section snippets

Materials

Synthesis of substituted polyaniline/chitosan composites

FTIR results

Conclusions

Mater. Chem. Phys.

Biosens. Bioelectron.

Carbohydr. Polym.

Synth. Met.

Carbohydr. Polym.

J. Hazard. Mater.

Carbohydr. Polym.

Biosens. Bioelectron.

Sens. Actuator, B Chem.

Synth. Met.

Carbohydr. Polym.

Sens. Actuator, B Chem.

Talanta

Synth. Met.

Synth. Met.

Mater. Chem. Phys.