We measured force–distance curves of polystyrene (PS)/poly (vinyl methyl ether) (PVME) blend thin films using atomic force microscopy (AFM) in order to pursue the possible usage of AFM as a tool for detecting viscoelastic properties of polymeric materials from a nanoscopic point of view. In quasi-static measurements of force–distance curves for a sample whose PS content equals 100%, both adhesive force and capillary force were measured separately. A phenomenon possibly assigned to pulling off of polymer chains by an AFM tip could also be observed for a sample whose PS content equals 60%. By changing the velocity of the AFM tip acting on a blend sample whose PS content equals 40%, we confirmed that the law of time–temperature reducibility holds even on such a nanoscopic scale. This blend sample behaved as a viscous fluid at room temperature, while its behavior became glassy when faster movements of the AFM tip were applied. A discussion on the future development of a new field of research which should be called “nanorheology" was also presented.

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ABSTRACT:The crystallization behavior and morphology of poly( e-caprolactone) (PCL)/poly(vinyl butyral) (PVB) blends containing carbon black (CB) were studied as functions of PVB and CB content. The presence of CB had no influence on the primary nucleation of PCL crystals or the spherulitic growth rate. They were only influenced by the blend ratio of PVB. The growth rates of spherulites were unchanged throughout the crystallization process, regardless of the CB content. The results indicate that the concentration of PCL at the front of growing spherulite remains constant during crystallization. The distribution of CB in the spherulites was observed using atomic force microscopy to explain these results.