Solid phase photopolymerization of pyrrole in poly(vinylchloride) matrix

doi:10.1016/j.eurpolymj.2005.05.029

European Polymer Journal

Volume 41, Issue 11, November 2005, Pages 2711-2717

https://doi.org/10.1016/j.eurpolymj.2005.05.029 Get rights and content

Abstract

Electrically conductive films were obtained by solid phase photopolymerization of pyrrole (Py) into a poly(vinylchloride) (PVC) matrix. We attempted to characterize the structure, electrochemical and thermal properties, and morphology of the resulting polypyrrole/PVC blend. The blend obtained has low conductivity and rather poor electroactivity due to the loss of conjugation length of polypyrrole (PPy) provoked by halogenation. Micrographs of cryofracture surface suggested two distinct phases, and thermogravimetric analysis revealed a low thermal stability of the blend. On the basis of our experimental results, we propose a reaction mechanism that explains the PPy formation in solid phase induced by UV light.

Introduction

Since their discovery, intrinsically conductive polymers (ICP) have attracted the attention of the industry and the scientific community due to their optical and electrical properties and been applied in a number of areas. Besides the electrochromism and the photoelectrochemistry of ICP, which are a consequence of their electrical properties, their conductivity can be engineered for appropriate electronic devices [1]. However, the application of ICP in the plastic and electro-electronic industries is limited by its poor mechanical properties. On attempting to overcome this feature, research groups have devoted their efforts to develop conducting and flexible films. Blends containing ICP and thermoplastics, polyamides, polyesters, or elastomers, are used in the production of materials for electrochromics [2], [3], [4], batteries [1], [2], [3], [4], [5], [6], sensors [7], [8], [9], [10], attenuators, capacitors, photodiodes [11], [12], [13], [14], photoelectrochemical cells [15], [16], [17], and antistatic coatings [1], [18], [19]. It is well established that the electrical, optical, and magnetic properties of ICP are strongly dependent on synthesis conditions, which can be chemical, electrochemical, or photochemical [20], [21]. In the last decade, the use of light had an important role in the development of the microelectronic industry and computer science, (from the point of view of the ultra fast information transmission) and as a source of energy. In addition, light can also be used to induce redox processes in ICP (e.g. photoelectrochromism [20]) or to induce the monomer oxidation for ICP formation. According to Kobayashi and co-workers [22], the photopolymerization of ICP can be divided in two categories: (i) photopolymerization using photocatalytic species and (ii) photoexcitation of the monomer. Similarly to the chemical synthesis of ICP, photopolymerization is based on the photochemical generation of an oxidizing agent capable of oxidizing the monomer and forming the polymer. Usually, the photocatalytic process uses the irradiation of a metal–ligand compound (e.g. [Ru(bpy)₂]Cl₂, [Cu(dpp)]BF₄, etc.) with visible or UV light to form an excited charge transfer compound which acts as a strong electron donor in the presence of an acceptor (cobalt complex [23], p-nitrobenzyl bromide [24], etc.). In addition, organometallic complexes such as ferrocene (and some derivatives) easily form donor-acceptor species in halogenated solvents [25].

According to Rabek and co-workers [25], the oxidative polymerization of pyrrole induced by UV irradiation in solution depends on the formation of FeCl₃ through a radical mechanism when using polyhalogenated solvents. Ueno and co-workers [26] prepared conductive blends with poly(vinylchloride) (PVC) and polypyrrole (PPy) using a PVC solution containing FeCl₃. Films of PVC/FeCl₃ were prepared by partially exposing cast and dried films to UV light to observe the formation of an image that was converted to an electric conductive form by exposing the film to pyrrole steam.

Considering that the formation of blends by conductive polymers with other construction polymers is a matter of current interest, and aiming to elucidate the mechanism of pyrrole photopolymerization in PVC matrix, blends of PVC and PPy were prepared by photoinduced polymerization of pyrrole in the solid phase, i.e., using a solid PVC matrix containing pyrrole and a donor–acceptor agent. The blends were characterized mainly by FTIR spectroscopy, cyclic voltammetry, thermogravimetric analysis, scanning electron microscopy, and X-ray photoelectron spectroscopy analysis.

Section snippets

Experimental

Poly(vinylchloride) (PVC) (100,000 gmol⁻¹, Aldrich) was kept in vacuum at 50 °C for 24 h before use. Tetrahydrofuran (THF, Aldrich) was used without further treatment. Ferrocene (Cp₂Fe, Sigma) was purified twice through sublimation. Pyrrole (Riedel-de-Häen) was purified by vacuum distillation. To prepare the films, PVC in THF solution (10%, wt/wt) was stirred constantly for 12 h. Soon afterwards, pyrrole (10⁻¹ mol l⁻¹) and Cp₂Fe (10⁻² mol l⁻¹) were added. Next, the solution was transferred to Teflon^®

Results and discussion

Fig. 1 shows the UV–vis absorption spectra of solutions containing PVC, pyrrole, and Cp₂Fe (in THF) irradiated at different periods. It is possible to observe the formation of the conducting polymer through the growing band at 560–575 nm corresponding to the polaronic transition at 2.2 eV [27]. In addition, it is observed the formation of ferricenium tetrachloroferrate, [Cp₂ Fe]⁺[FeCl₄] at ca. 500 nm, and the ferricenium ion, Cp₂Fe⁺Cl⁻, at 620–650 nm, which is responsible for the formation of the

Conclusions

The system discussed here gives an example of a polymeric system that can be converted into an electrically conducting form via UV light processing. This method can be used to prepare conducting blends by simply illuminating a mixture containing insulating polymers and monomers of conductive polymers. In addition, since UV light and lasers are ideal tools for patterning substrates, electrically conducting patterns can be generated directly via light exposure in the same way. The

Acknowledgements

A.W.R, M.H.K, and M.J.L.S thank CAPES for fellowships. The authors thank CNPq (PROFIX project no. 541058/01-0) and Fundação Araucária for financial support (project 2562) and Dr. Larry T. Taylor (Virginia Polytechnic Institute, USA) for XPS analyses.

References (36)

R.D. Rauh et al.
High coloration efficiency electrochromics and their application to multi-color devices
Electrochim Acta
(2001)
K.L. Levine et al.
Electrochemical behavior of the polypyrrole/polyimide composite by potential step amperometry
J Power Sources
(2003)
L. Lvova et al.
Multicomponent analysis of Korean green tea by means of disposable all-solid-state potentiometric electronic tongue microsystem
Sensors Actuators B
(2003)
A. Riul et al.
An electronic tongue using polypyrrole and polyaniline
Synth Met
(2003)
J.H. Sung et al.
Fabrication of microcapacitors using conducting polymer microelectrodes
J Power Sources
(2003)
K.S. Jang et al.
Characteristics of tantalum electrolytic capacitors using soluble polypyrrole electrolyte
J Power Sources
(2003)
T. Johansson et al.
Conductivity of de-doped poly(3,4-ethylenedioxythlophene)
Synth Met
(2002)
A.F. Nogueira et al.
Poly(ethylene oxide-co-epichlorohydrin)/NaI: a promising polymer electrolyte for photoelectrochemical cells
Solid-State Ion
(2001)
W.A. Gazotti et al.
Solid-state photoelectrochemical cell using a polythiophene derivative as photoactive electrode
Sol Energy Mater Sol Cells
(2001)
A. Dkhissi et al.
Theoretical investigation of the nature of the ground state in the low-bandgap conjugated polymer, poly(3,4-ethylenedioxythiophene)
Chem Phys Lett
(2002)

J.Y. Kim et al.

Enhancement of electrical conductivity of poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) by a change of solvents

Synth Met

(2002)

J.H. Chen et al.

Electrochemical synthesis of polypyrrole films over each of well-aligned carbon nanotubes

Synth Met

(2001)

W.A. Gazotti et al.

N. Belhaneche-Bensemra et al.

Characterization of rigid and plasticized PVC-PMMA blends: I—study of the miscibility

Ann Chim Sci Mater

(2003)

M.H. Kunita et al.

Deposition of copper sulfide on modified low-density polyethylene surface: morphology and electrical characterization

Appl Surf Sci

(2002)

M.A. Smit et al.

A modified Nafion membrane with in situ polymerized polypyrrole for the direct methanol fuel cell

J Power Sources

(2003)

J. Shan et al.

Morphology and microstructure of polypyrrole formed by electrochemical polymerization

Thin Solid Films

(1997)

M. Chakraborty et al.

Interpenetrating polymer network composites of polypyrrole and poly(vinyl acetate)

Synth Met

(1999)

Cited by (44)

Turning danger into opportunity: Ultraviolet (UV) irradiation-surface reconstruction effect of hydrophilic plastics and its application in plastic flotation separation
2023, Journal of Environmental Chemical Engineering
Plastic flotation shows a good application prospect in the field of waste plastic recycling. Nevertheless, surface reconstruction effect is highly likely to worsen the effect of plastic flotation separation. In order to avoid the fluctuation of plastic flotation separation process, it is urgent to explore the role of environmental factors on the reconstruction of hydrophilic and hydrophobic groups. Among various environmental factors, ultraviolet (UV) irradiation is one of the most important environmental factors affecting surface reconstruction effect. In view of this, in this work, we first used two common plastic modification methods, Fenton aging and polyaluminum chloride (PAC) modification, to hydrophilize six common plastics, namely PS, PVC, ABS, PMMA, PC, and PET. Then we studied the UV irradiation-surface reconstruction effect of hydrophilic plastics using flotation experiments. The results showed that UV irradiation can significantly enhance the surface reconstruction effect of hydrophilic plastics. More importantly, the wettability of plastic surfaces can be regulated by changing lighting conditions. Based on this, a novel UV irradiation-flotation process to separate PVC, ABS, and polyester (PMMA, PC, and PET) was successfully developed in this study. This work not only provides ideas for the further application of plastic flotation technology, but also lays a certain foundation for the development of novel and efficient UV irradiation-flotation processes.
PVC Degradation and Stabilization
2020, PVC Degradation and Stabilization
Digital light processing for the fabrication of 3D intrinsically conductive polymer structures
2018, Synthetic Metals
Citation Excerpt :
This challenge prevents these PPy formulations from being directly used with the DLP additive fabrication technique since the forces on the produced structures during fabrication cause the material to fail. Efforts have been made to improve their mechanical properties by incorporating large surfactant anions [13] or simultaneous polymerization of pyrrole with another polymer [12,27–30]. These hybrid polymer systems enable the overall material to take on the smart material properties of PPy and the mechanical properties of the secondary polymer.
Conventional methods to fabricate intrinsically conductive polymer actuators result in planar morphologies that limit fabricated devices to simplistic linear or bending actuation modes. In this study, we report a conductive polymer formulation and associated 3D printing fabrication method capable of realizing three-dimensional conductive polymer structures that are not subject to such geometric limitations. A light-based 3D printing technique known as digital light processing is employed due to its ability to fabricate complex microscale features in conjunction with a specially-formulated photosensitive polypyrrole resin. The performance of this fabrication system is characterized via feature resolution and depth of cure experiments, and the results are subsequently applied to the fabrication of 3D components. This technique enables the fabrication of novel electroactive polymer structures and provides a framework for advanced 3D electroactive polymer-enabled devices capable of complex modes of sensing and actuation.
Photopolymerization of pyrrole/methacrylate mixtures using α-cleavage type photoinitiators in combination with iodonium salt
2015, Synthetic Metals
Hybrid systems formulated with pyrrole and methacrylate monomers were photopolymerized with both UV (λ = 365 nm) and visible (λ = 470 nm) light. It is known that conducting polymers produced by electrochemical or chemical synthesis are intractable solids or powders which display poor mechanical properties and low processability. An advantage of the photopolymerization process is that it allows processability and mechanical properties of final polymers to be optimized by incorporating flexibilizers and different additives into photopolymerizable formulations. Mixtures pyrrole/methacrylate were photoactivated with the iodonium salt p-(octyloxyphenyl)phenyliodonium hexafluoroantimonate (Ph₂ISbF₆), in combination with 2,2-dimethoxy-2-phenylacetophenone (DMPA), 2-methoxy-2-phenylacetophenone (BZME) or the pair camphorquinone (CQ)/ethyl-4-dimethylamino benzoate (EDMAB). The Ph₂ISbF₆ in combination with DMPA or BZME was an efficient photoinitiator system under irradiation at 365 nm. Conversely, in mixtures photoactivated with Ph₂ISbF₆/CQ/EDMAB the polymerization of both pyrrole and methacrylate was comparatively slow. Microscopy studies revealed the absence of phase separation indicating that the mixtures pyrrole/methacrylate resulted in the formation of an interpenetrating polymer network. The electrical conductivity of the hybrid polymers increased markedly with the amount of polypyrrole as a result of the formation of a conducting polymer network in the insulating BisEMA matrix.
Hybrid assemblies by pyrrole polymerization on nano graphene oxide platelets
2015, Polymer
Oxidative polymerization of pyrrole on the surface of platelets of graphene oxide (GO) was demonstrated to generate polypyrrole/GO (PPy/GO) hybrid assemblies. The polymerization reactions were performed in GO acid dispersions using ammonium persulfate (APS) as an oxidant. Model kinetic reactions were carried out by ¹H NMR spectroscopy with APS at low temperatures. Evidence was found for an increase in the rate of polymerization of pyrrole in the presence of GO. IR and ESCA results indicate that the neutralization of the COOH groups on the GO may be due to interaction with the PPy. The morphology of PPy/GO assemblies analyzed by AFM revealed spherical particles of PPy agglomerated on the surface of GO platelets. Furthermore, TEM analysis indicated that polymerization of pyrrole occurred on both the surface of the GO and in between the GO layers.
This type of synthesis could offer an approach to the generation of new solid hybrids and allow systematic changes of their physical properties.
Template free method for the synthesis of Ag-PPy core-shell nanospheres with inherent colloidal stability
2014, Synthetic Metals
Citation Excerpt :
FTIR spectroscopy (Fig. 3) was performed to study the effect of silver nitrate concentration on PPy, strong nitrate doping vibrations were observed at approximately 1385 cm−1 with the incorporation of silver nitrate in the reaction [18,45]. The characteristic bands present at approximately 770 and 880 cm−1 might be ascribed to the CH and CC out of plane deformations, while the band present at approximately 1090 cm−1 may correspond to CH in plane vibrations [23,46–49]. The bands present at approximately 3400 cm−1 may be assigned to NH stretching in PPy [50].
Stable aqueous dispersions of silver–polypyrrole core–shell nanospheres have been synthesised in a template free method, utilizing the oxidative capabilities of ozone and silver nitrate. The core–shell nanospheres possess antibacterial and electroactive properties. Silver nanoparticles which are produced due to reduction of silver nitrate by pyrrole provide sites for the nucleation and growth of the polypyrrole shell. The morphology of the nanospheres was studied using electron microscopy and dynamic light scattering, while X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and UV–vis spectroscopy were used to study the chemical nature of the nanospheres. The electrochemical activity and thermal stability of the core–shell morphology has been studied using cyclic voltammetry and thermogravimmetric analysis, respectively. The core–shell nanospheres were studied for their antibacterial properties on Pseudomonas putida KT2440. The nanospheres reduced the viability of the strain as well as inhibited its growth.

View all citing articles on Scopus

View full text

Solid phase photopolymerization of pyrrole in poly(vinylchloride) matrix

Abstract

Introduction

Section snippets

Experimental

Results and discussion

Conclusions

Acknowledgements

Electrochim Acta

J Power Sources

Sensors Actuators B

Synth Met

J Power Sources

J Power Sources

Synth Met

Solid-State Ion

Sol Energy Mater Sol Cells

Chem Phys Lett

Synth Met

Synth Met

Ann Chim Sci Mater

Appl Surf Sci

J Power Sources

Thin Solid Films

Synth Met