Comparison of the Above Methods

It is important to note that care must be taken in determining the molecular weights of PATs using GPC. It has been reported by Berry, Yue, and McCullough that extensive aggregation occurs in regioregular PATs and this can lead to errors in the GPC [52]. We have seen samples of PATs that have of 130K by GPC (THF). 

This experiment was reproduced at least five times. However, eventually we observed (in the same sample) a of 25K. Therefore, some of the reported molecular weights could be the molecular weights of aggregates. 

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The differences in the estimated values are in most cases quite minimal. A comparison of the above methods is given in Table 1.6 in the context of an example (see Sect. 1.3.3, p. 28). 

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