Isotactic polystyrene film thickness

Fig. 13. A graph showing the variation of growth rate with the inverse of film thickness Ud) for isotactic polystyrene crystals grown at 180 C in nltrathin films. A step in the behavior can be seen at a thickness of 8 nm. At this temperature, this corresponds to the thickness of the single lamella, showing a change in thickness dependence once the film is thinner than the growing crystal. Reprinted from Ref. 98. Copyright (2002), with permission from Marcel Dekker, Inc.

Figure 3.49 Bright field TEM images and electron diffraction patterns of isotactic polystyrene crystallized at = 180°C in films of thickness d = ll nm (a) and 8 nm (b). These are very similar to the AFM images in films of the same thickness on different substrates in Figure 3.47c,e. Scale bars are 2 pm. FromTaguch et al. [66] with permission from Taylor Francis Group, http //www.iuformaworld.com.

Similar situations as in the case of isotactic polystyrene are encountered during the oxidation of polyethylene and polypropylene films. For the latter case, flakes of different thickness were used. The functional relationship between sample thickness and rate of oxidation was similar as in the previous case. Here, oxygen diffuses from both sides into the flakes (there is no agitation and [O2] = constant in the film). 

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