An inelastic electron tunnelling spectroscopy (IETS) study of poly(vinylacetate) poly(methyl methacrylate) and poly(vinylalcohol) adsorbed on aluminium oxide

Mallik, Robert; Pritchard, R. G.; Horley, C. C.; Comyn, J.

doi:10.1016/0032-3861(85)90154-5

Cited by 37 publications

(9 citation statements)

References 16 publications

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“…The examination of the differences between the bulk and thin PMMA films points to the hydrolysis of the ester group of the PMMA with the subsequent formation of a carboxylate ion . As illustrated in Figure b, by probing the sample very close to the chromium interface (washing off “bulk” polymer) an absorption band at 1672 cm -1 may be observed, which corresponds to the formation of a COO - group. , For the thin PMMA sample, the intensity of this absorption band is comparable to that of the CO absorption band at 1738 cm -1 . The intensity ratio between the absorption bands of the COO - and CO groups increases as the thickness of the PMMA layer decreases, due to the fact that for a thinner polymer film the relative concentration of the Cr−PMMA interfacial molecular species increases, and therefore, their contribution to the absorption become more evident.…”

Section: Resultsmentioning

confidence: 94%

Spectroscopic Study of the Chemistry at the Cr−PMMA Interface

et al. 2002

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The chemical reactivity of metal nanoclusters is largely determined by the size of the particles, and therefore the control of particle size in a given medium has been the topic of several interesting studies in recent years. In most of these studies, polymer molecules are used as stabilizing agents in the aggregation process of the nanoclusters, through their selective adsorption onto the surface of the growing particles, thus forming a barrier to van der Waals attractions. These interactions have resulted in the control of cluster growth without causing any detectable damage to the polymer. Despite a multitude of qualitative observations, no quantitative analysis has been provided to date which offers a relationship between the extent of the metal−polymer interactions (including the degree of damage to the polymer chain) and the size of the metal particles formed as a result of the polymer adsorption. To establish such a relationship and develop the basis for a theoretical and quantitative description of these processes, a fundamental understanding of the nature, strength, and mechanism of the metal−polymer interactions is necessary. In this work, metal surfaces have been used as models for metal particles. The interactions between chromium surfaces and thin films of adsorbed poly(methy methacrylate) have been investigated by X-ray photoelectron (XPS) and surface-sensitive infrared (PM-IRRAS) spectroscopies. The adsorption process results in the formation of a new species at the interface between chromium and PMMA, characterized by distinct spectral patterns, the reorganization of the metal surface molecules, and the reorientation of the polymer ester side chains.

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Section: Resultsmentioning

confidence: 94%

Spectroscopic Study of the Chemistry at the Cr−PMMA Interface

et al. 2002

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“…Previous studies have proposed that the surface hydroxides of alumina are capable of hydrolyzing the ester bond on the side chain of PMMA . This hydrolysis produces a carboxylate side chain, which bonds ionically with the surface of alumina as shown below.…”

Section: Discussionmentioning

confidence: 94%

Adsorption of PMMA on Oxidized Al and Si Substrates: An Investigation by High-Resolution X-ray Photoelectron Spectroscopy

et al. 2000

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The adsorption of medium molecular weight poly(methyl methacrylate) (PMMA) from an apolar solvent onto oxidized aluminum and silicon substrates has been studied by monochromated X-ray photoelectron spectroscopy (XPS). By recording the capacity of the solid surface for the polymer, by XPS, as a function of solution concentration, it has been possible to construct adsorption isotherms for the two systems under study. At low solution concentration, these isotherms are shown to conform to Langmuir adsorption and provide similar values of monolayer coverage, Γm, but significantly different values of the constant term, b, in the Langmuir equation were determined. At higher solution concentration, the adsorption isotherm was different due to an increase in Γm and a dramatic decrease in the constant b. Such observations are thought to result from a change in conformation of the adsorbed molecule at higher solution concentrations. Such effects are not associated with changes of conformation in solution but reflect the adsorption of a more compact molecule, which invariably forms fewer bonds with the substrate. The nature of the adsorption sites present in the oxidized metal substrates and their interactions with PMMA and conformation of the adsorbed molecules were interpreted from the high-resolution XPS spectra. These results were used to interpret the adsorption isotherms in terms of the acido-basic properties of the polymer and substrates, entropy of polymer solutions, and conformation of adsorbed molecules.

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“…For example, following the deposition of polymethyl methacrylate (PMMA) on oxidized aluminum surfaces and its analysis by inelastic electron tunnelling spectroscopy, Mallik et al [24] proposed the cleavage of the ester group of PMMA at the aluminum oxide surface, leading to its adsorption via carboxylate anions. In contrast, Sondag and Raas [23] suggested the formation of hydrogen bridges between the carbonyl groups of the polymer and the surface hydroxyl groups of the oxidized aluminum.…”

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confidence: 99%