AFM investigations of the initial stages of prepolymer film growth on aluminium

Gesang, T.; Höper, R.; Dieckhoff, S.; Fanter, D.; Hartwig, Andreas; Possart, W.; Hennemann, O.‐D.

doi:10.1016/0169-4332(94)00546-x

Cited by 10 publications

(5 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The aluminum samples were prepared by vapor depositing 2000 Å thick Al films on polished Si wafers. X-ray photoelectron spectroscopy indicated that the native oxide layer of the film was 20−30 Å thick, in agreement with published results . Prior to use, the samples were rinsed with acetone and deionized water.…”

supporting

confidence: 89%

See 1 more Smart Citation

Nanoscale Imaging of a Corrosion Reaction: Sulfuric Acid Droplets on Aluminum Surfaces

Dai

Freedman

et al. 1996

J. Phys. Chem.

View full text Add to dashboard Cite

The morphological changes of the liquid and solid phases occurring during the corrosion of aluminum by sulfuric acid were imaged in situ with nanometer resolution using scanning polarization force microscopy and conventional atomic force microscopy. The rate of reaction between the acid and the metal is highly dependent on the relative humidity. At high relative humidities, a dramatic spreading of the liquid droplets is observed that is indicative of sulfuric acid-induced aluminum corrosion. The liquid layer consists of a mixture of aluminum sulfate product and sulfuric acid. At low relative humidity, an aluminum sulfate precipitate is formed which segregates from the unreacted liquid acid. This phase separation inhibits further corrosion, in agreement with the results of previous experiments using infrared reflection absorption spectroscopy. The results of these experiments offer new insights into the mechanisms of chemical corrosion at gas-liquid-solid interfaces.Atmospheric chemical corrosion constitutes a severe threat to the structural integrity of many metals and, as such, is responsible for considerable economical loss. 1-4 For example, sulfuric acid droplets from acid rain or dew deposition is the principal cause of corrosion of aluminum. Since atmospheric corrosion reactions occur at the solid-liquid interface and involve submicrometer thick liquid films and droplets, their study constitutes a difficult challenge. Optical imaging and spectroscopy techniques are excellent and nonintrusive but lack the necessary resolution. Atomic force microscopy (AFM) has very high resolution, but it is unable to image liquids, since the contact of the tip causes capillary wetting and strong perturbation of the liquid surface. In this work, we use a new technique, scanning polarization force microscopy (SPFM), 5,6 to image liquids with nanometer resolution. In combination with infrared reflection absorption spectroscopy (IRAS), we were able to follow in unprecedented detail the physical and chemical changes occurring during the corrosion of aluminum by sulfuric acid droplets in humid environments.In the SPFM technique, the electrically charged tip of an AFM scans the surface at a distance of a few hundred angstroms. Maintaining this tip-surface distance is critical in order not to perturb the liquid surface. The SPFM can be operated also as a standard contact mode AFM, and in this case, only the solid substrate is imaged while any liquid deposit is locally displaced by the tip.The aluminum samples were prepared by vapor depositing 2000 Å thick Al films on polished Si wafers. X-ray photoelectron spectroscopy indicated that the native oxide layer of the film was 20-30 Å thick, in agreement with published results. 7 Prior to use, the samples were rinsed with acetone and deionized water. The experiments were always carried out in humidity-controlled chambers.In-situ IRAS studies revealed that hydrated aluminum sulfate is the principal product of the corrosion reaction. 8 The rate of corrosion, measured by the appearance of h...

show abstract

supporting

confidence: 89%

“…X-ray photoelectron spectroscopy indicated that the native oxide layer of the film was 20-30 Å thick, in agreement with published results. 7 Prior to use, the samples were rinsed with acetone and deionized water. The experiments were always carried out in humidity-controlled chambers.…”

mentioning

confidence: 99%

Nanoscale Imaging of a Corrosion Reaction: Sulfuric Acid Droplets on Aluminum Surfaces

Dai

Freedman

et al. 1996

J. Phys. Chem.

View full text Add to dashboard Cite

show abstract

“…Atomic force microscopy revealed the typical corrugation to be -30-50 nm (peak to valley) and the roughness to be -2-10 nm RMS (analysed area: 1 pm x 1 pm up to 3 pm x 3 pm). 19 The chemical surface constitutions of the substrates were investigated2' by XPS (VG Escalab Mk 2) and AES (Perkin Elmer 660). The surface constitution was to represent the one before application of polymer, because before polymer application the substrates have had contact with the atmosphere in short-term storage and because the application itself also was ex vacuum, contact with the atmosphere was also realized before the investigation of the substrate's chemical surface constitution.…”

Section: Experimental Substratesmentioning

confidence: 99%

Comparative film thickness determination by atomic force microscopy and ellipsometry for ultrathin polymer films

Gesang

Fanter²,

Höper

et al. 1995

Surface & Interface Analysis

Self Cite

View full text Add to dashboard Cite

Ellipsometry and atomic force microscopy (AFM) were used to study the film thickness of continuous and discontinuous polymer films in the 1-20 nm thickness range on smooth silicon wafers and on structured aluminium substrates. The methods of exploiting AFM for thickness measurements with a high spatial resolution are described.For continuous films, the AFM method is a direct one, i.e. it does not rely on any model. There is excellent agreement between AFM and ellipsometry in the 1-10 nm thickness range. Very small systematic deviations occur in this range but big deviations occur above 10 nm, and are discussed. The film preparation method, spin coating, was characterized to result in prepolymer films with a very homogeneous thickness.Discontinuous films of 2-9 nm thick were also evaluated by both methods of thickness determination. In tbis case, for one of the AFM approaches a model has to be used too. The agreement between both methods ranged from very good to poor, depending on the kind of sample and on the kind of AFM determination method.

show abstract

“…The prepolymer agglomerates usually do not fully cover the aluminum peaks, but cease on the slopes of the peaks …”

Section: Resultsmentioning

confidence: 99%

“…The second type of substrates were aluminum evaporation coatings . The findings are described elsewhere in detail . The coatings were applied onto silicon wafers by means of evaporation in a vacuum chamber.…”

Section: Methodsmentioning

confidence: 99%

Investigations on the Influence of Adhesion, Cohesion, and External Forces on the Formation of Ultrathin Polymeric Films

et al. 1996

Self Cite

View full text Add to dashboard Cite

The birth and growth of ultrathin polymer films out of solution were studied by means of atomic force microscopy (AFM). The system investigated consisted of a model substance for a curable high-temperature adhesive (a prepolymer of the dicyanate of bisphenol A) and as received silicon wafers or aluminum evaporation coatings. The application techniques, dip-coating and spin-coating, allow film formation either in nearly equilibrated conditions or with the influence of centrifugal acceleration, respectively. AFM reveals significant differences between the films depending on the application technique and the substrate, but in some instances there are surprising similarities. The comparative interpretation of the findings results in the proposal of a model for the film formation of the investigated systems.

show abstract

AFM investigations of the initial stages of prepolymer film growth on aluminium

Cited by 10 publications

References 5 publications

Nanoscale Imaging of a Corrosion Reaction: Sulfuric Acid Droplets on Aluminum Surfaces

Nanoscale Imaging of a Corrosion Reaction: Sulfuric Acid Droplets on Aluminum Surfaces

Comparative film thickness determination by atomic force microscopy and ellipsometry for ultrathin polymer films

Investigations on the Influence of Adhesion, Cohesion, and External Forces on the Formation of Ultrathin Polymeric Films

Contact Info

Product

Resources

About