Simulating Migration of Polymer Chains

Simulating Migration of Polymer Chains, Methods, Fig. 1 Confonnation of a 30-bead chain in a linear shear flow at different times. The chain shown will exhibit a periodic tumbling motion if observed for long periods of time... 

Simulations reveal structural interactions between the migrating dopant ion and the host lattice in which polymer chains respond to the migrant by distorting from planarity. As would be expected, this interaction increases rapidly with the flexibility of the chains. In Section 6.2 we see that in nonconjugated polymers (i.e., those with no n electronic component to favor chain planarity), the host dopant interaction plays an essential role in the jump mechanism in migration. 

Flexible polymers in a pressure-driven flow fleld migrate towards the center of the channel, because of hydrodynamic interactions. The local shear rate stretches the polymer and the resulting tension in the chain generates an additional flow field around the polymer. This flow field becomes asymmetric near a no-slip boundary and results in a net drift towards the center of the channel [191-193]. Recent simulations [193,194] show that hydrodynamic lift is the dominant migration mechanism in pressure-driven flow, rather than spatial gradients in shear rate. Recently, we used... 

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