Polystyrene, isotactic microscopy

Figure 8.1. (a) Spherulites growing in a thin film of isotactic polystyrene, seen by optical microscopy with crossed polars (from Bassett 1981, after Keith 196.3). (b) A common sequence of forms leading to sphertililic growth (after Bassett 1981). The fibres consist of zigzag polymer chains. 

The derived activation energy for SPS chain mobility at the crystal-growing front is 5.4kJ/mol, which is lower than that of isotactic polystyrene, which is 6.5kJ/mol. Despite a wide range of Tc used, however, the sample crystallinity estimated by Fourier transform infrared spectroscopy remains unchanged. Interconnected domains with a width of approximately 1.8 pm are readily observable in all the crystallized samples under phase contrast microscopy, and the phase-separated structure is conserved within SPS spherulites whose diameters are increased with increasing Tc. 

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