The morphology of ultrathin films of normal alkane C60H122 has been examined with atomic force microscopy at temperatures between 25 and 150 °C. The films were prepared by spin-casting of diluted alkane solutions on graphite. Epitaxial alkane layers, which are formed directly on the substrate surface, are characterized by lamellar morphology. A lamellar width of 7.5 nm corresponds to the length of the extended C60H122 molecule. A topmost layer was formed of nanocrystals up to 10 nm in height. The nanocrystals consist of multiple layers of C60H122 lamellae, which are oriented parallel to the substrate. Imaging of the alkane films at elevated temperatures has revealed that the nanocrystals melted around 95 °C, while the epitaxial layers have been observed at temperatures up to 140 °C. In some locations, a spontaneous reorientation of alkane lamellae has been noticed at temperatures in the 130−140 °C range.

We investigate the spinodal decomposition of a polymer mixture, at both critical and offcritical compositions, using atomic force microscopy. Phase separation in the bulk is imaged using tapping mode on the surface of microtomed samples. The generated surface profiles, revealed in height images, are analyzed according to their in-plane spinodal morphology and their (perpendicular) height distribution. The former is characterized in terms of the periodicity of the structure and volume fraction of coexisting phases, both in the percolation and cluster regimes. The average height profiles are shown to be bimodal with a height step, ∆h, ranging from 1 to 7 nm, for the temperature quench depths spanned. ∆h is timeindependent but depends linearly on annealing temperature and therefore on the composition difference between coexisting phases. This temperature dependence allows us to extrapolate to the mixture's critical temperature. A blend of tetramethyl bisphenol A polycarbonate and polystyrene was employed for this demonstration.

Atomic force microscopy (AFM) and electric force microscopy (EFM) have been applied for compositional mapping of a number of elastomers and related multicomponent materials. Several aspects of optimizing AFM experiments on polymers are discussed. AFM images revealed changes of EPDM morphology caused by crosslinking and by loading with fillers [carbon black (CB) and silica particles] and oil. It was shown that the morphology of isotactic polypropylene (iPP)/EPDM vulcanizates, which were studied with AFM and EFM, depends on the ratio of components, degree of cure and processing conditions. Diffusion of oil from the elastomer component to the matrix is evidenced in the AFM images. Selective distribution of CB in the iPP matrix is responsible for the electric conductivity of the thermoplastic vulcanizate.

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