Nanorheology of Polymer Blends Investigated by Atomic Force Microscopy

Abstract

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.

Atomic force microscopy observation of enamel surfaces treated with selfetching primer

“…Surface hardness can be determined by AFM from force curves 33,34) . The elastic properties of bone and bone marrow 35) and gelatin 36) have been determined by AFM.…”

Nanorheology of Polymer Nanoalloys and Nanocomposites

“…The velocity of 200 nm/s gave 3.2 MPa, while that of 60 m/s gave 10.2 MPa. We speculate that this behavior is related to the glass-rubber transition seen in the bulk material at room temperature as shown in Figure 3.14 [Nakajima et al, 1997]. The glass-rubber transition occurs at the nanometer scale.…”

“…The phasecontrast image, together with the topography image using the tapping mode, is difficult to interpret, and it provides at most qualitative information. We have been engaged for many years in using AFM with a sufficient understanding of its advantages and disadvantages to develop methodology suitable for polymeric soft materials: namely, nanorheology [Nakajima et al, 1997] and nanotribology [Terada et al, 2000;Komura et al, 2006]. The peculiar feature of these methods is the positive usage of sample deformation, a feature that becomes troublesome in imaging.…”

Probing the viscoelastic response of glassy polymer films using atomic force microscopy

“…The atomic force microscope (AFM) has become a powerful and versatile tool in many research fields because of its ability to image various surfaces and probe the mechanical, chemical, and thermodynamic properties of a surface down to nanometer scales while under different conditions [1][2][3][4][5][6][7][8][9][10][11][12][13]. Recently, there has been considerable interest in using an AFM to study the mechanical properties of polymer films and other soft matter including biological systems [26,27].…”