Shear-thinning and isotropic-lamellar-columnar transition in a model for living polymers

KR Prathyusha and AP Deshpande and M Laradji and PBS Kumar, SOFT MATTER, 9, 9983-9990 (2013).

DOI: 10.1039/c3sm51715b

A model consisting of short polymer segments, capable of self assembling to form a branched network through the interaction of their ends, is considered. We investigate the mechanistic origins of a shear induced isotropic-lamellar-columnar transition, reported earlier in this model for living polymers. We find that these structures arise only in the presence of a potential barrier in the end point interaction between polymer segments. To elucidate the role played by long range solvent mediated forces, we have carried out simulations with and without the hydrodynamic interactions between the polymers and have seen that these structures are present in both these cases. We also show that the shear induced layering in these systems is a bulk phenomena and boundary interactions have little effect on the transition. The monomer volume fraction and viscosity of the background solvent are shown to have significant effects on determining the morphology of the flow-induced structures. We demonstrate that the structures obtained are indeed non- equilibrium states induced by the shear.

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