Effect of reagent concentrations used to synthesize polypyrrole on the chemical characteristics and optical and electronic properties of the resulting polymer

Lei, Junting; Cai, Zhihua; Martin, Charles R.

doi:10.1016/0379-6779(92)90318-d

Cited by 215 publications

(106 citation statements)

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“…To the authors' knowledge, the highest previously reported density for PPy was 1.44 g/cm 3 . 28 The high degree of porosity, microstructural, and molecular defects, including molecular species not connected to the cross-linked polymer network, and rough surface account for the low mechanical strength and modulus of the CP films, as the pores and internal defects act as stress concentrators or plasticizers. 16,29,30 The higher conductivity of the SP films likely arise from increased conjugation length, as no difference in long-range order or chemical composition between SP and CP films could be detected by X-ray diffraction ( Figure S1b) or Raman spectroscopy ( Figure S1d).…”

Section: Resultsmentioning

confidence: 99%

The Role of Unbound Oligomers in the Nucleation and Growth of Electrodeposited Polypyrrole and Method for Preparing High Strength, High Conductivity Films

et al. 2012

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Polypyrrole is a material with immensely useful properties suitable for a wide range of electrochemical applications, but its development has been hindered by cumbersome manufacturing processes. Here we show that a simple modification to the standard electrochemical polymerization method produces polypyrrole films of equivalently high conductivity and superior mechanical properties in one-tenth of the polymerization time. Preparing the film as a series of electrodeposited layers with thorough solvent washing between layering was found to produce excellent quality films even when layer deposition was accelerated by high current. The washing step between the sequentially polymerized layers altered the deposition mechanism, eliminating the typical dendritic growth and generating nonporous deposits. Solvent washing was shown to reduce the concentration of oligomeric species in the near-electrode region and hinder the three-dimensional growth mechanism that occurs by deposition of secondary particles from solution. As artificial muscles, the high density sequentially polymerized films produced the highest mechanical work output yet reported for polypyrrole actuators. ABSTRACT: Polypyrrole is a material with immensely useful properties suitable for a wide range of electrochemical applications, but its development has been hindered by cumbersome manufacturing processes. Here we show that a simple modification to the standard electrochemical polymerization method produces polypyrrole films of equivalently high conductivity and superior mechanical properties in onetenth of the polymerization time. Preparing the film as a series of electrodeposited layers with thorough solvent washing between layering was found to produce excellent quality films even when layer deposition was accelerated by high current. The washing step between the sequentially polymerized layers altered the deposition mechanism, eliminating the typical dendritic growth and generating nonporous deposits. Solvent washing was shown to reduce the concentration of oligomeric species in the near-electrode region and hinder the three-dimensional growth mechanism that occurs by deposition of secondary particles from solution. As artificial muscles, the high density sequentially polymerized films produced the highest mechanical work output yet reported for polypyrrole actuators.

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Section: Resultsmentioning

confidence: 99%

The Role of Unbound Oligomers in the Nucleation and Growth of Electrodeposited Polypyrrole and Method for Preparing High Strength, High Conductivity Films

et al. 2012

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“…O mecanismo através do qual os polímeros conduzem eletricidade tem sido apresentado detalhadamente na literatura 40,41 . A consideração mais importante do ponto de vista químico e também foco desta revisão considera que "um aumento da condutividade eletrônica é obtido quando são preparados polímeros com maior ordenamento molecular e supermolecular" [40][41][42][43][44] . Polímeros mais ordenados molecularmente contém poucos defeitos que interrompem a conjugação da cadeia polimérica, como p. ex.…”

Section: Figura 1 Estruturas Dos Polímeros Condutores Intrínsecos (Punclassified

Síntese de polímeros condutores em matrizes sólidas hospedeiras

Maia¹,

Paoli²,

Alves³

et al. 2000

Quím. Nova

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Recebido em 7/12/98; aceito em 8/6/99 CONDUCTIVE POLYMER SYNTHESIS IN SOLID HOST MATRICES. This review discusses the methods used to prepare conductive polymers in confined environments. This spatial restriction causes formation of defect-free polymer chains in the interlayer as porous cavities of inorganic hosts. The properties of the different composites obtained are a synergist combination of the characteristics of the inorganic host and the polymer. This opens new perspectives for the preparation of these materials and widens its potential applications.Keywords: conductive polymers; inorganic matrices; composites. REVISÃO INTRODUÇÃOUm histórico sobre tecnologia de polímeros evidenciaria, sem dúvida alguma, que uma das propriedades mais importantes destes materiais sintéticos é a capacidade de comportar-se como excelentes isolantes elétricos, tanto para altas freqüências quanto para voltagens. No entanto, nos últimos anos uma nova classe de polímeros orgânicos tem sido desenvolvida, cuja importância está relacionada à possibilidade de conduzir eletricidade 1 . Os membros desta nova classe de materiais, chamados de "metais sintéticos", possuem uma característica em comum: longos sistemas π conjugados, ou seja, uma alternância de ligações simples e duplas ao longo da cadeia. O interesse evidente é combinar em um mesmo material as propriedades elétricas de um semicondutor ou metal com as vantagens de um polímero.Desde a década de 60, é conhecido que moléculas orgânicas que apresentam duplas ligações conjugadas podem exibir propriedades semicondutoras. O desenvolvimento inicial foi inibido pelo fato que as cadeias rígidas, em uma estrutura conjugada, também produzem uma intratabilidade extrema, tal que a maioria dos primeiros exemplos de polímeros condutores eram infusíveis, insolúveis e, portanto, de pouco valor tecnológico. No começo dos anos 70 Shirakawa e Ikeda 2,3 demonstraram a possibilidade de preparar filmes auto-suportados de poliacetileno pela polimerização direta do acetileno. O polímero produzido apresentou propriedades semicondutoras que atraiu pouco interesse até 1977, quando MacDiarmid e cols.4 descobriram que, tratando o poliacetileno com ácido ou base de Lewis, era possí-vel aumentar a condutividade em até 13 ordens de grandeza. Este processo envolve a remoção ou adição de elétrons da cadeia polimérica, sendo denominado "dopagem". O termo dopagem é utilizado em analogia com os semicondutores inorgânicos cristalinos, sugerindo semelhanças com os polímeros intrinsecamente condutores (PICs). Em ambos os casos a dopagem é aleatória e não altera a estrutura do material. No entanto, na dopagem de um polímero as impurezas não são introduzidas nas cadeias, mas sim nas suas "vizinhanças". A interação impureza-cadeia gera deformações e "defeitos carregados" localizados, responsáveis pelo aumento na condutividade 5 . Outra diferença significativa está na quantidade de dopante utilizada. Enquanto os semicondutores apresentam "impurezas" que atuam como dopantes, da ordem de ppm, os PICs chegam a ter 50% em ma...

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“…This may be accomplished either electrochemically (8,12) or with a chemical oxidizing agent (7,10,30,33). Both of these methods can be used to do template synthesis of conductive polymers.…”

Section: Template Synthesis Of Conductive Polymersmentioning

confidence: 99%

Nanomaterials: A Membrane-Based Synthetic Approach

Martin

1994

Science

Self Cite

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Materials with nanoscopic dimensions not only have potential technological applications in areas such as device technology and drug delivery but also are of fundamental interest in that the properties of a material can change in this regime of transition between the bulk and molecular scales. In this article, a relatively new method for preparing nanomaterials, membrane-based synthesis, is reviewed. This method entails synthesis of the desired material within the pores of a nanoporous membrane. Because the membranes used contain cylindrical pores of uniform diameter, monodisperse nanocylinders of the desired material, whose dimensions can be carefully controlled, are obtained. This "template" method has been used to prepare polymers, metals, semiconductors, and other materials on a nanoscopic scale.

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Effect of reagent concentrations used to synthesize polypyrrole on the chemical characteristics and optical and electronic properties of the resulting polymer

Cited by 215 publications

References 31 publications

The Role of Unbound Oligomers in the Nucleation and Growth of Electrodeposited Polypyrrole and Method for Preparing High Strength, High Conductivity Films

The Role of Unbound Oligomers in the Nucleation and Growth of Electrodeposited Polypyrrole and Method for Preparing High Strength, High Conductivity Films

Síntese de polímeros condutores em matrizes sólidas hospedeiras

Nanomaterials: A Membrane-Based Synthetic Approach

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