Polypyrrole optical properties

Variation in Polypyrrole Optical Properties As a Function of Growth Conditions... 

The second method is the synthesis of copolymers or derivatives of a parent conjugated polymer with more desirable properties. This method is the more traditional one for making improvements to a polymer. It modifies the structure of the polymer to increase its processibility without compromising its conductivity or its optical properties. All attempts to do this on polyacetylene have failed as they always significantly reduced its conductivity. However, such attempts on polythiophenes and polypyrroles proved more fruitful. 

Intercalation of electroactive polymers such as polyaniline and polypyrrole in mica-type layered silicates leads to metal-insulator nanocomposites. The conductivity of these nanocomposites in the form of films is highly anisotropic, with the in-plane conductivity 10 to 10 times higher than the conductivity in the direction perpendicular to the film. Conductive polymer/oxide bronze nanocomposites have been prepared by intercalating polythiophene in V2O5 layered phase, which is analogous to clays. °° Studies of these composites are expected not only to provide a fundamental understanding of the conduction mechanism in the polymers, but also to lead to diverse electrical and optical properties. 

A. Watanabe, M. Tanaka, and J. Tanak, Electrical and optical properties of a stable synthetic metallic polymer polypyrrole. Bull. Chem. Soc. Jpn., 54, 2278-2281 (1981). 

K. Dutta and S.K. De, Transport and optical properties of Si02-polypyrrole nanocomposites... 

J. Jang, Y. Nam, and H. Yoon. Fabrication of polypyrrole-poly(A-vin-ylcarbazole) core-shell nanoparticles with excellent electrical and optical properties. Ac v. Mater, 17(11) 1382-1386, June 2005. 

FIGURE 7.5. Evolution of the optical properties (a,b) and film thickness(c) as a function of time for a polypyrrole film grown potentiostatically on a Pt sputter-deposited film electrode at +0.60 V (SCE) using an aqueous solution of pyrrole (0.025 M) and KNO3 (0.5 M). (From Ref. 19). 

Polymer films that combine the optical properties of PEDOT and polypyrrole have been produced by either casting a solution of the PEDOT/PSS suspension followed by electrochemical polymerization of... 

Chromatic changes caused by electrochemical processes were originally described in the literature in 1876 for the product of the anodic deposition of aniline [271]. However, the electrochromism was defined as an electrochemically induced phenomenon in 1969, when Deb observed its occurrence in films of some transition metal oxides [272]. Electrochromism in polypyrrole was first reported by Diaz et al. in 1981 [273]. Electrochromism is defined as the persistent change of optical properties of a material induced by reversible redox processes. Electronic conducting polymers have been known and studied as electrochromic materials since the initial systematic studies of their electronic properties. 

Optical absorption spectra of a thin film of polypyrrole as a function of degree of doping. See text for a description. Patil, A. O., Heeger, A. J., and VVudl, F. "Optical Properties of Conducting Polymers." Chem. Rev., 88,183-200(1988). 

The electrical and optical properties of polyacetylene (CH) , polyaniline (PANI), polypyrrole (PPy), polythiophene (PT), po-ly(p-phenylene vinylene) (PPV), poly(p-phenylene) (PPP), and poly(thienylene vinylene) (PTV) are some of the extensively studied conducting polymers [3,1049]. 

We began our template synthesis work in 1985 by electrochemically synthesizing the electronically conductive polymer polypyrrole within the pores of a nanoporous polycarbonate filtration membrane [10]. Since then, we [9,11-16] and others [26-35] have explored, in some detail, the electrochemical, electronic, and optical properties of template-synthesized conductive polymers. I review this work in this chapter. Topics discussed include the membranes used to do template synthesis, the electronic properties of template-synthesized conductive polymer fibrils and tubules, and the morphology of the template-synthesized conductive polymers. 

The prototypes of a large class of polyaromatic molecules that have been found to possess relevant electrical and/or optical properties are polyparaphenylene (PPP) and its oligomers (PP ), polyparaphenylenevinylene (PPV) and its oligomers (PV ), and the series of rylenes (Ry ). In the class of polyheteroaromatics, we consider oligopyrroles (Py ) and polypyrrole (PPy), oligothio-phenes (Th ) and poly thiophene (PTh), and some derivatives. 

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