Order in lyotropic polymer solutions

The development of liquid-crystalline phases and the rheological properties of lyotropic polymers are discussed in so far as they are related to the formation of fibers and films. 

The mechanical properties of fibers and films are governed by the orientation distribution of the polymer chains (see Section 6.4.1). Hence the discussion is focused on the development of the orientation of the chains in the polymer solution and on the formation of orientation during spinning of fibers. Good surveys of current theories on the formation of liquid-crystalline phases have been given by Odijk and Ciferri and Marsano. Later in this chapter we shall present a modified Maier-Saupe theory recently developed by Picken of our laboratory.  

Poly(l,4-benzamide), abbreviated here as PpBA, was the first nonpeptide, synthetic condensation polymer reported to form liquid-crystalline phases. Of technological importance is 

Characterization of dilute solutions of PpPTA and PpBA by determination of the persistence length, Lp, and the molecular weight distribution has been carried out by Arpin and Strazielle, Ying and Chu, and Ying et The results depend on the experimental method, such as 

Viscosity measurements of solutions of low-molecular-weight PBO in chlorosulfonic acid and other solvents yielded a Mark-Houwink exponent of 1-85, which is very close to the value expected for a rod-like polymer. Depolarized dynamic light scattering of PBT solutions in chlorosulfonic acid resulted in a persistence length of 64 nm, which is one of the highest persistence lengths known when compared with those of other rigid-rod polymers.  

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