Polymer Capture with Electroosmotic Flow

The steady-state net flux of the fluid, due to EOF, is given by Equation 8.90. Since the fluid flow must be continuous in the system, all the fluid elements in the cis compartment must flow into the pore, assuming that all nonlinear hydrodynamic effects such as the intermittency and turbulence are absent. This means that at a distance R away from the pore entrance, the surface area of the 

at distances near the pore, the velocity gradient is the strongest, and at large distances, it falls off like R.  

Combining Equations 8.90, lAl, and 9.35, the critical capture radius follows as 

The number concentration of the polymer chains c R) at a distance R from the pore is obtained as follows. In the steady state, the divergence of the flux is zero. In the presence of diffusion and EOF, the divergence of the flux in the steady state is given in the spherical polar coordinate system as 

Near rc, the polymer concentration decreases exponentially from the bulk value to zero with a decay length of 27rDr / /ol- Using Equations 7.10, 7.44, 8.90, and 9.36, we get this decay length as Q.QlRg/a /, with a defined in Equation 9.37. 

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