(217bi) Investigation of Translation Diffusion of Flexible Macromolecules in Vicinity of Functional Solid Substrates Via Computationally Efficient Hi-Fidelity Brownian Dynamics Simulation

Absorbing substrates with distinct functional groups in conjugation with macromolecules fid applications in many areas of science and engineering including fast single chain separation and detection techniques, microfabrication, photovoltaic devices, etc. To this end, elucidating the effect of hydrodynamic interaction (HI) and polymer-wall interaction strength on dynamical behavior of macromolecules should greatly facilitate design of material and devices targeted for the aforementioned applications.

It is well established that the diffusive behavior of polymeric chain near substrates scales as N^-v, where N is the number of monomers per chain and v is the scaling exponent, which varies between ½ for an HI dominant chain in good solvent to 3/2 (measured experimentally) for weakly absorbed flexible chains.

To date Brownian Dynamics (BD) has been successfully used to investigate single chain dynamics in dilute solution. More recently the bead-spring description of short polymeric chain (N<100) have been utilized to find that the lateral diffusion scales as ¾<v<1. However, traditional BD formulations generally neglect the deviation of the elastic response of macromolecules from the classical models such as Hookian or Langevin force law due to both confinement and monomer-wall interactions. Moreover extension of the simulation technique to longer chains is limited since the computational cost scales with O(N^3/2) .

To overcome these difficulties we have developed a new computationally efficient method for simulation of the bead-rod model of macromolecules. Specifically we demonstrate (i) hi-fidelity of our approach in capturing single chain elasticity, and its conformity with the flexible single chain experimental technique, (ii) The new O(N) incorporation of polymer-solid interface HI via multipole expansion formulation based on Barnes and Hut method and finally (iii) scaling of translational diffusion of flexible polymeric chain at vicinity of functional solid substrates as a function of polymer-interface interaction strength.