Polymer Films on Electrodes: XVI . In Situ Ellipsometric Measurements of Polybipyrazine, Polyaniline, and Polyvinylferrocene Films

Successive thicker P(3MeTh) layers are analysed by ex situ conventional and imaging ellipsometry. Thin films display a smooth surface, are compact and homogeneous while for a growth charge above 20 mC cm − 2 the polymer structure modifies to a still uniform but less dense layer. A two-layer model is used and a mathematical procedure is developed to obtain, simultaneously, from the experimental ellipsometric parameters, Z and c, the thickness and the complex refractive index of P(3MeTh) films grown up to 80 mC cm − 2 . Thicker polymer layers are disordered and present a high degree of surface roughness.

Section: Resultssupporting

confidence: 53%

The heterogeneous growth of P(3MeTh)—an ellipsometric study

Abrantes¹,

Correia²,

Jin³

2001

“…It is well documented that at the beginning of the polymer deposition process a very compact and dense polymer, of 150 Á/200 nm in thickness, is formed. However with subsequent polymer chain growth, as in this study, loosely packed porous structures are produced [21,22].…”

Section: Resultsmentioning

confidence: 74%

The electrochemical synthesis of polypyrrole at a copper electrode: corrosion protection properties

Fenelon

Breslin

2002

173

Pyrrole was successfully electropolymerized at a copper electrode in a near neutral sodium oxalate solution to generate a homogeneous and adherent polypyrrole film. The growth of these films was facilitated by the initial oxidation of the copper electrode in the oxalate solution to generate a copper oxalate pseudo-passive layer. This layer was sufficiently protective to inhibit further dissolution of the copper electrode and sufficiently conductive to enable the electropolymerization of pyrrole at the interface, and the generation of an adherent polypyrrole film. These films remained stable and conducting for periods exceeding eight days and exhibited significant corrosion protection properties in acidified and neutral 0.1 mol dm (3 NaCl solutions even on polarization to high anodic potentials. #

“…It has been reported by several authors that the polymer shrinks down upon reduction, and this phenomenon has been interpreted as due to the release of solvent and counterions [20]. Since the films of 20 and 20+30 growth cycles present the same structure and the applied methodology permits to determine of the actual thickness of the polymer , it was also used with the same films, after polymer reduction (Fig.…”

Section: Resultsmentioning

confidence: 99%

Structural modifications during conducting polymer formation — an ellipsometric study

Abrantes

Correia

Savić³

et al. 2001

Polyaniline films potentiodynamically synthesised on gold substrates are analysed ex situ by conventional and imaging ellipsometry (at constant wavelength). Polymers grown up to 50 cycles appear to be homogeneous, whereas different structures are displayed by thicker layers. The memory effect, induced by the polymer electrochemical characterisation, in subsequent polymer growth, is demonstrated. In the case of thin films, a reliable methodology has been successfully employed to obtain, from the ellipsometric parameters Z and , the refractive index, the extinction coefficient and the thickness of polymer layers. This approach also allowed us to quantitatively evaluate the magnitude of polymer swelling upon oxidation (11-22%). Furthermore, the surface morphology is well evidenced by the results obtained by imaging ellipsometry.