Comparative studies on Langmuir–Schaefer films of polyanilines

Ram, Manoj K.; Adami, Maurice Zarb; Sartore, Marco; Salerno, Marco; Paddeu, Sergio; Nicolini, Claudio

doi:10.1016/s0379-6779(99)00024-7

Cited by 49 publications

(51 citation statements)

References 30 publications

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“…It has been previously observed that POEA possess strong interaction with lignin derivatives which present similar chemical structures to humic substances. 21,24 Also this observation is consistent with a proton transfer reaction between humic acids and the herbicide atrazine (6-chloro-N 2 -ethyl-N 4 -isopropyl-1,3,5-triazine-2,4-diamine), as detected by FTIR. By comparison with the spectrum of primary doped POEA using HCl (protonation), 18 it can be extracted from Figure 2 that the spectra of the mixed solutions containing POEA + fulvic acid (B, C and D) show that the POEA is doped as indicated by the characteristic band around 1340 cm -1 (1327 cm -1 in the case of spectrum E) assigned to C-N + stretching of radical cation (polaron) supporting what was observed by UV-Vis spectroscopy.…”

Section: Spectroscopy Investigation Of the Interaction Between Poea Asupporting

confidence: 83%

“…A globular morphology was observed for all POEA, which is consistent with other works in the literature. 21 However, the globule size has increased significantly when the SA POEA films were immersed into buffer solution containing fulvic and humic acids, respectively. The increase in the globule size is due to the complexation of POEA with the humic substances wich are, relatively big structures and then result in globules with higher volume than POEA itself.…”

Section: Spectroscopy Investigation Of the Interaction Between Poea Amentioning

confidence: 99%

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Studies on the interaction between humic substances and conducting polymers for sensor application

Venâncio¹,

Filho²,

Constantino³

et al. 2005

J. Braz. Chem. Soc.

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Neste trabalho, foi investigada a interação entre substâncias húmicas e um polímero condutor (poli-(o-etoxianilina) -POEA), ambos em solução e filmes automontados. Os resultados mostram que as substâncias húmicas dopam a POEA por protonação, isto é evidenciado por espectroscopia UV-Vis e Raman. Os estudos de microscopia de força atômica (AFM) em filmes automontados mostram haver um aumento na rugosidade do filme polimérico quando este é exposto a substâncias húmicas (ácidos húmico e fúlvico), o que evidencia a existência de interação entre a POEA e as substâncias húmicas. Esta mudança na morfologia é reversível com a lavagem dos filmes com água, em concordância com as medidas elétricas, possibilitando a aplicação em sensores. Um sistema sensor formado por um arranjo de diferentes unidades sensoriais foi capaz de distinguir substâncias húmicas em solução aquosa, como é mostrado pela análise multivariada (análise da componente principal), o que é importante para controle da qualidade de água e solo.The interaction between humic substances and poly(o-ethoxyaniline) (POEA), a conducting polymer, was investigated for both solution and self-assembled films. The results have shown that the humic substances induce a doping of POEA by protonation, as indicated by UV-Vis and Raman spectroscopies. The atomic force microscopy (AFM) studies on the self-assembled films have shown that the average roughness of the polymer film has increased after exposing it to humic substances (fulvic and humic acids), consistent with the interaction between POEA and humic substances. However, this change in morphology is reversible by washing the films with water in agreement with the electrical data allowing using this system in sensor applications. Here, the sensor formed by an array of different sensing units was able to detect and distinguish humic substances in aqueous solution, as shown by multivariate analysis (principal component analysis). The motivation to detect humic substance comes due to its importance in terms of quality control of water or soil.

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Section: Spectroscopy Investigation Of the Interaction Between Poea Asupporting

confidence: 83%

Section: Spectroscopy Investigation Of the Interaction Between Poea Amentioning

confidence: 99%

Studies on the interaction between humic substances and conducting polymers for sensor application

Venâncio¹,

Filho²,

Constantino³

et al. 2005

J. Braz. Chem. Soc.

View full text Add to dashboard Cite

show abstract

“…This result is also providing information on the film quality as it is related to the equivalent circuit drawn for a uniform polymer film [10]. In fact, polyaniline derivatives do not have the tendency to form well-organized films, as it was shown by AFM microscopy [13]. On the other hand, AFM imaging of the POAS nanocomposite materials synthesized with carbon nanotubes showed a better film organization, as reported in Fig.…”

Section: Resultsmentioning

confidence: 53%

Improved nanocomposite materials for biosensor applications investigated by electrochemical impedance spectroscopy

Carrara

Bavastrello

Ricci

et al. 2005

Sensors and Actuators B: Chemical

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“…Conducting LB and Langmuir-Schaefer (LS) films have also been studied with AFM [16][17]. Riul et al, [18] characterized LB films of parent PANI to optimize experimental conditions for the formation of stable Langmuir monolayers and their subsequent transfer onto solid substrates.…”

Section: Contact Modementioning

confidence: 99%