Controlled Polymerization of Silver Nanoparticle Dispersed poly (aniline and 3–Bromo Aniline) Composites: “One–Pot” Synthesis, Characterization, Morphology, and Electrochemical Properties of Novel Copolymer Nanocomposites

doi:10.21203/rs.3.rs-3889867/v1

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Controlled Polymerization of Silver Nanoparticle Dispersed poly (aniline and 3–Bromo Aniline) Composites: “One–Pot” Synthesis, Characterization, Morphology, and Electrochemical Properties of Novel Copolymer Nanocomposites

https://doi.org/10.21203/rs.3.rs-3889867/v1

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The formation of materials between silver nanoparticles (AgNPs) and a polyaniline matrix can lead to various composites, depending on the specific conditions imposed by the researchers basedon the targets and applications initially intended. These nanocomposites often exhibit enhanced electrical, optical, and catalytic properties compared to either component considered by itself. Therefore, such new materials are sought–after and targeted for synthesis. New copolymer composites of silverdispersed poly(aniline–co–3–bromoaniline) copolymer nanocomposites at different molar ratios were synthesized by insitu chemical oxidative polymerization methods. Characterization includes UV–vis spectroscopy, FT–IR spectroscopy, X–ray diffraction, and scanning electron microscopy.The optical absorption absorption peaks at 338 and 596 nm are ascribed to the n–π* electronic transitions, respectively. The formation of benzenoid and quinoid rings of the copolymer system was confirmed by FT–IR spectroscopy. XRD spectral data confirms the amorphous nature of the copolymer. The SEM image depicts the agglomerated and spherical granular morphology with average sizes of 150 to 300 nm. According to a study on electrical conductivity, conductivity decreases as the feed ratio of 3–bromoaniline monomer increases1.13×10^–5 to 5.16×10^–8 S cm^–1.

Electrical Conductivity

Aniline

3–Bromoaniline

Copolymerization

Silver Nanoparticle

Nanocomposites

Polyaniline (PANI) is an organic semiconducting polymer; it is of great interest in research because of its electrical conductivity properties and mechanical and environmental stability. The presence of π–conjugation in the polymer chain results in delocalization of electrons giving rise to the electrical conducting property of the material. Due to the special electrical properties, mechanical properties, and optical properties of the conducting polymers, research on conjugated polymers and their composites has drawn the attention of numerous researchers in different fields [1]. The average electrical conductivity of corresponding polyaniline bases is 1.4 × 10^–8 S cm^–1; the density of the material is 1.245 g cm^–1. Therefore, PANI is a p–type semiconductor whose work functions are found to be in the range of4.42–4.78 eV. The advantages of such materials involving PANI, namely, environmental stability, low cost, and simplicity of synthesis of polyaniline conducting polymers have led to a wide range of possible commercial industrial uses for these materials[2].Various electronics and instrumentation, sensors, rechargeable batteries, conductive coatings, electromagnetic shielding, biotechnology and separation membranes are among the current types ofapplications [3].The electrical properties of the conjugated polymers can be tuned chemically, electrochemically, or even photochemically, and they can be regulated by doping levels [4–6].The polyaniline emeraldine base is doped with acid to generate a salt; this salt as an excellent ability to conduct electricity [7]. For the development of metal–polymer composites (MPCs), numerous efforts have been made by using emulsion technology, sol–gel techniques, and in–situ chemical oxidative polymerization techniques [8–9].

The fundamental issue with polyaniline is that it has poor industrial potential due to its limited solubility in a variety of organic solvents [10]. Its practical applications are constrained due to the interactions of hydrogen bonds between amine moieties [11]. Hence, substituted anilines can be considered as targets to disenable the strong intermolecular forces of hydrogen bonding arising from bond donor groups and to make the interactions softer and more London forces related. These “next–generation” designs are focused how to improve the profile of polyaniline–containing materials by improving their conductivity. The polymer chain's rigidity is also reduced by substituent atoms in the backbone, which may lead to an increase in solubility properties [12].

Halogen–substituted polyanilines have been developed and characterized, including those that are fluoro–, chloro–, and iodo–substituted [13–15]. Despite having electron donating groups, the polymers electrical conductivity values are found to be lower (10^–3 to 10^–1 S cm^–1)than those of unsubstituted polyaniline, but they have good solubility characteristics in common organic solvents such as DMSO, NMP and have a significant impact on their electrical conductivity [16, 17]. According to Kang and Yung and co-workers, substitution with a fluoro and chloro electronegative groups reduces a polymer's conductivity (< 10^–6S cm^–1) [18]. Neoh et al. in 1990 also determined that the conductivity of polyaniline substituted with iodine and chlorine were approximately 10^–6 S cm^–1 [19].These research findings evidenced thatthe conductivity and processability of the polymers are significantly impacted by the functional groups.

Achieving copolymerization of aniline with various functional group monomers, such as amides, organic acids, and aniline derivatives, is another straightforward objective; this strategy helps to enhance the processability of the material. Depending on the copolymer's composition, as studied and reported by Basavarajaet al. in 2015 and Chen et al. in 2000, it was discovered that the resulting materials were found to possess improved mechanical properties [20, 21]. There have been few reports of investigations on the polymerization of aniline counterparts with electron–withdrawing groups (EWGs), such as m–bromoaniline copolymers [22]. Although the detailed study of conducting polymers is a challenging one, it is well acknowledged that charge transfer occurs between the polymer and dopant in such molecular systems [23]. A counterion obtained from the dopant is produced as a result of this charge transfer, along with a polymerbased ionic center which is able to be delocalized. The dopant gets reduced to an anion while the polymer is oxidized to help create a polymer which can be containedin regularly–spaced places for localization of cations.

Herein, we report a “one–pot” synthesis of soft–template assisted aniline and m–bromoaniline copolymer. The reactions were carried out under various concentrations in the presence of DBSA surfactantwhich acts as a soft template and ammonium persulphate which acts as the oxidizing agent. During this polymerization, controlled addition of silver nanoparticles is also dispersed to help obtain hybrid polymer materials. The purpose of dispersing the silver nanoparticle into the polymer matrix is tohelp achieve such materials through synthesis; through this research, we can seek a greater understanding ofthe influence of inorganic particles towards charge transfer processes (in polymers). The UV–Visible and FT–IR spectroscopic methods were used to help characterize the resultant nanocomposites (below). Employing XRD, SEM, and four probe methods, the crystallinity, shape and electrical conductivity of these nanocomposites are examined and characterized.

2.1 Materials

Aniline (Rankem–India) and 3–bromoaniline (Hi–media, India) are purified under low pressure and stored at low–temperature as they await the time for use with the planned reactions. Ammonium persulfate (APS) and conc. HCl was purchased (E–mark, India). Dodecyl benzene sulfonic acid (DBSA) and sodium hydroxide (NaOH) were purchased and used as received (Hi Media, India). Silver nitrate (AgNO₃) was purchased from Merck (India). The solvents such as NMP, DMSO and DMF used herein were purchased and used without further purification (Hi Media, India). Double distilled water was also used for the preparation of the polymeric materials reported herein.

2.2 Synthesis of silver nanoparticles

The silver nanoparticle was prepared by following a known literature procedure [24]. First, a 3.26 g sample (0.10 M) of DBSA was dissolved in 90 mL of distilled water through the action of excessive stirring. Then, a portion of 0.189 g of aniline (0.010 M) is added gradually to the reaction mixture and stirred thoroughly until a transparent solution was formed. After this time, silver nitrate solution (0.010 M) (0.339 g) was added to the above solution in a drop–wise manner. Then, the solution was stirred well for 15 min and subsequently heated to 90^o Celsius. Then, 0.137 M (0.54 g) of NaOH solution was added to the reaction mixture. By this route, the formation of silver nanoparticles was generated and the mixture was heated further (90^o) for approximately 1 h while constant stirring was maintained. The synthesized silver nanoparticles, coated with DBSA colloids were cooled without any additional treatment. As a result, the silver nitrate was transformed into silver nanoparticles of less than 20 nm in diameter.

2.3 Synthesis of DBSA–doped Ag dispersed Poly(An–co–3–BA) copolymer

Firstly, 0.326 g (0.010 M) of surfactant was added into ~ 80 mL of distilled water. Then, a portion of 0.050 M of aniline and 3–bromoaniline were added to the above reaction mixture and mixed well. Then ~ 10 mL of 1.0 M dilute hydrochloric acid was also added (dropwise) into the reaction mixture; the mixture was continuously stirred to help form and sustain a homogeneous solution. Then, a mixture solution (colloidal solution) of 1.0 mL of silver nanoparticles was added to the reaction mixture (total quantity 100 mL). Then, 10 mL of 0.10 M of ammonium per sulphate was added to help start the polymerization; it was then stirred continuously for 12 h under ice–cold water bath conditions. A dark greenish precipitate was formed. Our intention to obtain DBSA–doped Ag dispersed poly (An–co–3–BA) nanocomposites was realized by different methods of characterization (see below). This is a common type of complexation in which AgNPs are dispersed within a polyaniline matrix. The AgNPs may be physically entrapped or chemically bound to the PANI matrix.

Finally, the green coloured substance is filtered and cleaned with distilled water, acetone and methanol. The product was dried in a vacuum oven at 40⁰C for about 6 h. A similar process was used to synthesize the different copolymers generated for 3:2 and 3:1 composition. The synthesis mechanism is shown in Scheme 1.

At first, the reaction mixture was a colourless solution. In time (after 24 h), the solution turned blue and then dark blue, indicating that PANI dimers and oligomers were formed and are present. This synthetic method involves rapid staining; the polymerization continues during an induction period. The speed and efficiency of the method depends on several factors, such as the nature of the oxidant and the concentration of the reactants. Most conducting electrical polymers able to be produced can be deposited in the form of thin films bearing different layers; different polymers show several oxidation states. Hence, their conductivity depends upon their oxidation states. By removing an electron polymer by anion doping, the polaronic form of half the oxide is obtained. Similarly, by removing the second electron, an oxide dipole form is produced. Consequently, the PANI–EB formula demonstrates the highest conductivity between PANI–LE and PANI–PB.

2.4 Instrumentation

A double beam UV–Visible spectrophotometer model ELICO SL–218 was used to record the absorption spectra of the materials. FT–IR spectra were recorded by SHIMADZU 8400S in the region of 400 to 4000cm^–1 using KBr pellets. By employing a scanning electron microscope (HR–SEM) HITACHI 6600L device operating at 20 kV, the surface morphology of the synthesized copolymer nanocomposites were examined. The sample's X–ray diffraction pattern was acquiredusing a Philips X'Pert Pro X–ray diffractometer at 40 kV with nickel–filtered CuKα radiation (λ = 1.5402). The study was performed at 10°/min rate in the diffraction angle range 2 of10° to 80°.The pellet was prepared by compressing the samples using a vacuum press at 12 MPa to create a sample of a diameter of 13 mm. Using a Keithley 6517 B electrometer, the DC electrical conductivity of the pelletized samples was investigated. The RF 8901 spectrofluorometer from Shimadzu was used to conduct the PL study.

3.1 Solubility

Polymer solubility is a critical and also tuneable physical property of the material. Solubility tests for the surfactant–aided poly (An–co–3–BA) and silver–embedded copolymer was performed using various polar solvents such as dimethyl sulfoxide (DMSO), N–methyl–2–pyrrolidone (NMP) and di–methyl formamide (DMF). This study reveals that the polymer is soluble in polar solvents due to the surfactant molecule which decreases the rigidity of the polymer backbone. The improvement of solubility of the copolymer may be due to the action of the silver atoms which help reduce the cross linking of the copolymer chains; the plasticizing effect of the polymer chains increases the brittleness of the polymer films. The polar bromo– group could take part to some degree in formation of hydrogen bonding, which changes solvation properties and improves their solubility in polar solvents [25]. Moreover, there could be the occurrence of Ar–Br activation with Ag atoms. The doping of polymer with DBSA produces counter ions which improves the solubility of the copolymer.

3.2 Analysis of UV–Visible spectra

The optical absorption spectrum of surfactant aided Ag dispersed poly (An–co–3–BA) copolymer is shown in Fig. 1. The peak at 338 nm is attributed to the π–π* transition of the phenyl ring; another peak at 596 nm is ascribed to the n–π* transition quinoid moieties [26]. It is assisting in extending the π conjugation between the phenyl rings along the polymer chain and also the process of charge transfers from the benzenoid segment HOMO level to the LUMO level [27]. The substitution groups on the benzene ring cause on average a larger torsional angle that gives rise to a blue shift to be observed. As a result, the reduced shift indicates the formation of nanostructured copolymers and shows that the presence of DBSA molecules in the polymer matrix exist after the polymerization is achieved. The dispersed silver nanoparticles pairs with the anilinium ion and forms an ionic complex affording a strong interaction between DBSA dopant molecules and polymer composites [28]. More energy is required for the electronic transitions in the complex. The presence of bromine substituent in the copolymer chain causes the spectral blue shift in the material, whereas in other cases in other materials the bromine substituent(s) would result in a red shift[29–30].

In a conjugated polymeric molecule, the bromine electron–withdrawing groups can limit the electrical charge's ability considerably [31]. The absorption peaks confirm the existence of exciton bonding in the polyaniline which favours the formation of polarons (“quasi particle used in condensed matter physics to understand the interactions between electrons and atoms in a solid material”) and bipolarons (“molecule or part of a macromolecular chain containing two positive charges in a conjugated system”, Wikipedia, accessed 2023 October) and thus supports the existence of p–type conductivity.

Depending on the reaction conditions, AgNPs may aggregate within copolymer matrixes, forming clusters or larger structures. These aggregated structures can have unique optical and electronic properties and are important in applications such as sensing (molecular sensors) and catalysis (molecular and heterogeneous catalysts).

3.3 FT–IR Spectral Studies

IR spectroscopy of a pure material may help carefully assign the types of functional groups present in the sample. Figure 2 shows the FT–IR spectra of surfactant aided Ag silver embedded poly (An–co–3–BA) nanocomposites and the spectral values were assigned. The spectra of the synthesized nanocomposites reveal the following characteristic spectral bands. These were observed at 3221, 3050, 2932, 1569, 1488, 1289, 1142, 1036, 807 and 545 cm^–1. The peak at 1305 cm^–1 is related with the C–N stretching in a secondary aromatic amine functional group. The peak at 2932 cm^–1 is assigned to the N–H stretching in the amine. The appearance of the broad band at 1142 cm^–1 is attributed to the C–N stretching vibration in the N = Q = N group. The peak at 545 cm^–1 is due to the C–N–C bending [31].

There are additional assignments that are related to the hydrocarbon nature of the material: The peak at 3221 cm^–1 is attributed to the C–H aromatic stretching of the surfactant molecule. The formation of benzenoid and quinoid rings in the copolymer is confirmed from the peaks at 1569 and 1488 cm^–1. The peak located at 1569 cm^–1is assigned to a C = C bond of the quinoid ring, whereas the peak at 1488 cm^–1 arises due to the vibration of the C = C group associated with the benzenoid ring. The characteristic peak at 1035 cm^–1 is assigned to the bromine atoms in the polymer chain. The peak at 1136 cm^–1 due to electron delocalization confirms the copolymer's electrical conducting character [32]. The peak at 807 cm^–1 is due to the C–H out–of–plane bending.

This data helps support the presence of electrical conductivity of copolymer due to the electron delocalization in the groups present and under IR analysis. The salt is categorized as the emeraldine type. It is present in its most useful form of polyaniline due to its high stability at room temperature. The material is composed of two benzenoid units and one quinoid unit situated alternately; this organic material is known to the community as p–type semiconductor. Core–shell structures in which the Ag is the core, are formed within the copolymer matrix. The AgNPs which serve as the “cores” are each surrounded by a shell of polyaniline copolymer. This configuration can provide additional stability and control over the properties of the hybrid composite material.

3.4 XRD spectral Data Results

XRD is a powerful and singular structuralmethod in obtaining experimental data on the identity of the molecules and a host of geometrical parameters including the stacking of the “lattice” planes and in helping categorize the material crystallographically, not unrelated to aspects of mineralogy. Figure 3 shows the XRD spectrum of surfactant-aided Ag embedded poly(An–co–3–BA) copolymer. It shows two peaks at 22^o and 25^o which reveals the amorphous nature of the copolymer. The increasing concentration of bromo-aniline increases the intermolecular interaction which crystallizes easily when compared to the pure amorphous nature of solid polyaniline. The spectral peaks observed at 32^o, 46^o, and 72^owere found to be oflow intensity and are in agreement with Ag data of JCPDS no.85–1355. The silver particles have been immersed in the polymer matrix, which would explain the low intensity. At higher concentration of bromoaniline monomer the amorphous character decreased. This is attributed to the periodicity parallel to the polymer chain which was electrochemically reduced [34]. This indicates the more ordered arrangement of the polymer chain matrix complexed with the silver nanoparticles and results in a material of a crystalline nature. This is also due to arrangement of monomer and comonomer molecules in the polymer chain structures. Hence the polymer chain may give rise to regions in one sample which are amorphous in some regions and crystalline in nature in other regions. The amorphous nature derives from including the aniline monomer and the partial crystalline nature of the material derives from the inclusion of the bromoaniline moiety into the polymer chain. Therefore, this copolymer chain is comprised of crystalline, semi crystalline and amorphous characteristics even before we start to discuss the presenceof Ag. This is the required property of any polymer during industrial processing soto obtain desired flexibility and stability of thin films. The formed copolymer may be random or alternate or even of a block copolymer sequence, depending upon the monomer reactivity during copolymerization. These arrangements of monomers in the copolymer structure may also serve to vary the crystalline and amorphous characteristics.

In this hybrid material, PANI and AgNPs may interact at the molecular level, leading to the formation of hybrid materials in whichthe properties of both components are intricately combined.

3.5 Surface morphology

Figure 4 (i, ii, &iii) depicts the SEM micrograph of the material, described as surfactant–aided Ag embedded poly (An–co–3–BA) nanocomposites. It is observed from these SEM images that the polymer nanocomposites depict the agglomerated and spherical granular morphology; the materials exhibit particles with an average diameter of 150 to 300 nm. It is observed that the copolymers formed are in agglomerated states; the structures included are both even and uneven, colloid particles are noticed. There are numerous smooth, flat–like nanostructured copolymers observed, each with an interconnected network of particles possessinga high surface area. Aniline nucleates create stacks between them which are held together by interactions between oligomers that contain phenazine. In the synthesis, nucleates are thought to have limited solubility in water; hence, they become hydrophobic, and attract the monomer droplets which adhere and polymerize to furnish polymer granules. The appearance and development of new granules on their surface simultaneously to form fused granular morphology [35].The spherical morphology of the copolymer is due to the coiling of polymer chains in the globular particles. However, the confined spherical morphology can be obtained by doping of DBSA surfactant molecules which act as soft templates; the template is itself of an approximate spherical shape. The shape of the template relates to the polymer formation into confined spheres. This evidenced that the controlled polymerization occurs inside the micelle which favours such shape and size. It is noticed that the silver nanoparticles are encapsulated well in the polymer matrix due to the strong affinity of silver for the many available nitrogen donor atoms which offer their lone pairs. The DBSA doped copolymer shows decreased particles when comparing to the bulk copolymer which shows the larger particle size. It reveals that the polymerization takes place inside the micelle core; coiling of the polymer chain inside the micelle core helps determine the shape of the nanosized materials.

As may be ascertained by inspecting the SEM images, the silver particles are well adhered on the PANI substrate due to the strong affinity of silver to nitrogen donor atoms indicating there are no interface issues in binding. This indicates that nanosized inorganic particles possess a nearly spherical morphology which is able to be embedded nicely and influences strongly this novel composite.

In this case, there is no deliberate involvement of “templates”; only the monomer, comonomer and the oxidant are taken into the aqueous solution of water which can form homogeneous solutions, once the free radical is formed, the polymerization reaction begins, its charge carriers are formed on the nitrogen atom during oxidation. The nitrogen atom centres in the polyaniline allow for points of electrochemical oxidation. During such oxidation, i.e., formal removal of electrons, a positive polaron is generated in the polymer chain; it will deform the chain structure considerably. Usually, oxidative polymerization may be considered as the formation of covalent bonds between monomer molecules by abstracting two protons; two electrons also having been removed, there is the joining of two parts of the polymer to form a single covalent bond.

There are many types of linkages able to be formed between monomer units. For example, in the case of aniline, “head–to–head”, “tail–to–tail” and “head–to–tail” configurations are possible. In our case of copolymerization, reactions favour the smooth deposition of polymer chain comprising different monomers of different repetition, different arrangements of monomer sequences leading to different type of copolymers such as random, alternate or block copolymer type materials within short ranges of 300nm lengths. Further deposition of chains by polymer propagation will take place as reactions repeat; due to the amorphous and crystalline nature of the chains, they merged togetherand align themselves to have highly thickened flake or granulated type structures composed of a layered nature where the materials are deposited between each stack. Hence, the porosity between each stackcan be observed by way ofthe SEM photographic data (Fig. 4).

3.6 Electrical Conductivity

The electrical conductivity of surfactant aided Ag–dispersed poly (An–co–3–BA) copolymer nanocomposites depicts the higher electrical conductivity of 1.13×10^–5S cm^–1. This may be due to the Ag nanoparticles which helps enhance the delocalization of the charges found in the polymer. The conductivity of the DBSA–doped copolymer is caused by the delocalization of charge transfer between the polaron units and conjugated π–bonds in the polymer backbone. The reaction between protons in DBSA and imine nitrogen atoms in the copolymers generally helps to determine the conductivity value [36]. The inclusion of electronegative bromine atoms in the polymer chain may reduce the charge transfer between the polarons and conjugated π–bonds, which could explain the decreasein conductivity observed. The increased channelling character of Ag nanoparticles enhances the mobility of the charge carriers along the polymer backbone [37]. The electrical conductivity value drops when the feed m–bromoaniline level is concentrated more, as shown in Table 1.

Also, the bromoaniline concentration appears to control the charge transfer rate. It is widely known that the conjugated structure, primarily accountable for the electronic conduction, develops flaws as a result of the doping process. However, due to the presence of electronegative brominated aniline present at the side chain, which significantly lowers the charge carrier and enhances solubility, the creation of regular structural ordering helps boost the level of electron delocalization.

Table 1

Electrical Conductivity Values of DBSA Doped Ag Dispersed Poly (An–co–3–BA).
Copolymer compositions of different molar ratios	Conductivity ( S cm^–1)
PANI	1.0 ×10^–2
PANI–DBSA	1.98×10^–2
Poly (An–co–3–BA) DBSA–Ag 3:1	1.13×10^–5
Poly (An–co–3–BA) DBSA–Ag 3:2	1.17×10^–6
Poly (An–co–3–BA) DBSA–Ag 3:3	5.16×10^–8

The lower electrical conductivity in the case of the sample bearing the 3:3 ratio is due, we propose, to the presence of electronegative bromine atoms that reduces conjugation in the benzene ring of the polymer chain. The optical band gap was found to be 2.47 eV with the existence of indirectly allowed transitions. At this position, charge conduction is not only afforded by free carriers (electron & hole) such as in the case of intrinsic semiconductors; charge conduction here involves the formation of polarons and bipolarons. As the applied voltage is increased, the movement or formation of polarons and bipolarons increases rapidly, contributing to higher values of current through the sample. However, its conductivity is also influenced by other factors including its electrochemical redox state, pH, humidity, and temperature. The electrical conductivity of the polyaniline increases exponentially with increasing temperature. Upon proton doping, new radical cation centers are formed in the materialat the imine nitrogen atoms. The electronic conduction in polyaniline therefore is believed to be due to these charge carriers. The new copolymer of the functional polyaniline system prepared herein is interestingly found to be a p–type semiconductor; this makes it very attractive for further research purposes, because of its thermal stability and good solubility, as well as plasticity. These are the most sought–after requirements of the properties needed for industrial processing of materialsinto desired thin films. And, as mentioned above, the p–type conductivity of this material is also confirmed.

Chemical oxidative polymerization was used to create copolymers of aniline and 3–bromoaniline with various chemical compositions and to study these resulting materials by a variety of techniques. The study depicts and discusses the agglomerated and spherical granular morphology of the material with the average granule size being 150 to 300 nm. Due to the limited solubility of the nucleates in water, droplets stick to finished polymer granules and start to form new granules on their surface, resulting in the fused granular morphology. The loss in conductivity may be due to a reduction in the charge transfer between the polarons and conjugated bonds caused by the presence of electronegative bromine atoms in the polymer chain. The electron–withdrawing characteristics of bromine substituents in the polymer units serve to restrict the electrical charge's capacity to spread effectively in a conjugated polymeric system, leading to more locally oxidized polymeric units. The copolymer nanocomposites can act as hole transporting layers in the optoelectronic devices since its conductivity values are within the range of semiconductors: 1.13 ×10^–5 to 5.16 ×10^–8 S cm^–1. Transport properties can be measured and assessed: such properties in these conducting polymers involve different possible chemical mechanisms. A number of charge transport mechanisms will depend on both molecular structure and microstructure. Mechanisms will allow us to understand how certain microstructures are produced. Thus, mechanisms depend on both complex molecular and morphological structures. Hopping of charge carriers along and between polymer chains, tunnelling between high–conductive crystallites embedded into amorphous matrixes, electron phonon interactions play the significant role in the charge transfer mechanism of such polymers. The synthesized copolymer compound can be used as e.g. a humidity sensor and it can be used at various energy levels (i.e., even at low temperature to the ambient room temperature). Furthermore, we would expect the lifetime of the sensor to be high due to its stability. Our future interest is to convert this new copolymer polyaniline of p–type semiconductor into thin films for fabricating solar cells.

Acknowledgments

The authors are thankful to the Centre for Research, Bannari Amman Institute of Technology and Sri Ramakrishna Mission Vidyalaya College of Arts and Science, Coimbatore for continuous encouragement. David G. Churchill acknowledges KAIST for continued research support.

Author Contributions

The TRR requires that all authors take public responsibility for the content of the work submitted for review. The contributions of all authors must be described in the following manner:

The authors confirm contribution to the paper as follows:

Structure of work and synthesis work: Jeeva A, Vijayanand PS
Data collection: Jeeva A, Ashokan S
Analysis and interpretation of results:

Vijayanand PS, Ashokan S

Draft manuscript preparation:

Vijayanand PS, David G. Churchill, Ashokan S,

All authors reviewed the results and approved the final version of the manuscript.

Conflicts of interest

The authors declare that they have no conflict of interest.

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Scheme 1 is available in the Supplementary Files section

No competing interests reported.

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Scheme 1.Synthesis mechanism of Poly (An–co–3–BA) DBSA–Ag copolymer

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Controlled Polymerization of Silver Nanoparticle Dispersed poly (aniline and 3–Bromo Aniline) Composites: “One–Pot” Synthesis, Characterization, Morphology, and Electrochemical Properties of Novel Copolymer Nanocomposites

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Abstract

Figures

1. Introduction

2. Experimental methods

2.1 Materials

2.2 Synthesis of silver nanoparticles

2.3 Synthesis of DBSA–doped Ag dispersed Poly(An–co–3–BA) copolymer

2.4 Instrumentation

3. Results and discussion

3.1 Solubility

3.2 Analysis of UV–Visible spectra

3.3 FT–IR Spectral Studies

3.4 XRD spectral Data Results

3.5 Surface morphology

3.6 Electrical Conductivity

4. Conclusion

Declarations

References

Scheme

Additional Declarations

Supplementary Files

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