Weill-des Cloizeaux theory

The theory based on this assumption is expected to give zeroth order predictions of global polymer properties, and is usually called the blob theory. However, this nomenclature does not seem relevant to the author (see Section 1.4). Hence, in this book, we call it the Weill-des Cloizeaux theory. 

The Weill-des Cloizeaux theory has acquired considerable popularity in recent years, because its basic assumption (eq 1.4) permits analytical calculation of various polymer properties in non-0 solvents. However, we should not expect it to be more than a semi-quantitative theory. For its improvement Francois et al. [3] proposed allowing y in eq 1.2 to vary with i — j according to either... 

The Weill-des Cloizeaux theory assumes that no expansion takes place within subchains shorter than aN. On this assumption we may consider a chain model which consists of Gaussian subcoils, each being made of Nc beads and interacting with one another. With such a subcoil viewed as a blob, this model is often referred to as the blob model. However, it is important to recognize that the Weill-des Cloizeaux theory concerns interactions between beads but not those between blobs. Therefore, contrary to many other authors, the author does not consider it relevant to call it the blob theory. 

When Nc is set equal to zero, the Weill-des Cloizeaux theory appears to reduce to the earlier e theory of Peterlin [7] and Ptitsyn and Eizner [8] (see... 

To calculate k) theoretically we must determine rj(r) by solving the equations of motion for the chain. Akcasu and Gurol [41] in 1976 attacked this on the basis of the Kirkwood diffusion equation [42], and Akcasu et al. [43] presented a more general theory in a review article of 1980. In what follows, without going to mathematical details, we summarize some important results on for Gaussian chains. Benmouna and Akcasu [44] and Akcasu et al. [43] extended the calculation of to non-Gaussian chains by invoking the Weill-des Cloizeaux approximation, eq 1.4. However, as mentioned in Section 1, this approximation seems too crude to explore excluded-volume effects on Q, quantitatively. 

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