Stiff-flexible polymers formation mechanisms

Lastly, we have determined that in addition to polymer structure, the addition order of materials, such as polymer, surfactant and salt, to a formulation affects the compositional range of coacervate formation and the coacervation mechanism. Depending on the flexibility of the polymer structure, the mechanisms of coacervation in the presence of added electrolyte can vary. Poly (4-vinyl pyridine)-LAS-NaCl systems show a polymer collapse mechanism with the formation of a super-salt when salt and polymer are pre-mbced. However, for the stiff cellulosic polymers, the pre-mixing of salt and polymer before surfactant addition enhances micelle-bridging without complete polymer collapse. Also, the addition... 

The formation of elastic networks from semiflexible cytoskele-tal filaments requires cross-linkers. As discussed below, filaments as stiff as F-actin or MTs do not form the same kinds of sterically trapped entanglements that can form in flexible polymer melts and, therefore, do not maintain shear stresses for times that are relevant for cell mechanics. Therefore, the viscoelastidty of the cell and of cytoskeletal preparations in vitro depends very strongly on the affinity and geometry of the bonds between filaments formed by various aoss-linkers, such as those listed in Table 1. 

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