Hydrodynamic Aspects of Macromolecular Solutions 



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t 



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Fig. 2 - Mohr's circle and second order stresses 



for instance. For both of these reasons we should be encouraged to consider 

 for ourselves the response of flexible molecules being convected within flows. 



We can adopt for this purpose the simplest model of the flexible molecule, 

 according to which there exists no hydrodynamic interference between its dif- 

 ferent parts. This proves a limited but nevertheless highly fruitful model. 



A la.rge flexible molecule possesses many, say IC* links, virtually free to 

 rotate at points of connection. Relative motion between the macromolecular 

 links and the solvent in their immediate neighborhood results in dissipation of 

 energy (because of the smallness of the Reynolds number, this dissipation, F, is 

 quadratic in the velocities of the relative motion). In the absence of inertia, 



