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We employ 3D Langevin Dynamics simulations to study the dynamics of polymer chains translocating through a nanopore in presence of asymmetric solvent conditions. Initially a large fraction ($>$ 50%) of the chain is placed at the textit{cis} side in a good solvent while the $trans$ segments are placed in a bad solvent that causes the chain to collapse and promotes translocation from the $cis$ to the $trans$ side. In particular, we study the ratcheting effect of a globule formed at the textit{trans} side created by the translocated segment, and how this ratchet drives the system towards faster translocation. Unlike in the case of unbiased or externally forced translocation where the mean first passage time $langle tau rangle $ is often characterized by algebraic scaling as a function of the chain length $N$ with a single scaling exponent $alpha$, and the histogram of the mean first passage time $P(tau/langletau rangle)$ exhibits scaling, we find that scaling is not well obeyed. For relatively long chains we find $langle tau rangle sim N^alpha$ where $alpha approx 1$ for $varepsilon/k_{B}T > 1$. In this limit, we also find that translocation proceeds with a nearly constant velocity of the individual beads(monomers), which is attributed to the coiling of the globule. We provide an approximate theory assuming rotat ional motion restricted on a 2D disc to demonstrate that there is a crossover from diffusive behavior of the center of mass for short chains to a single file translocation for long chains, where the average translocation time scales linearly with the chain length $N$.
We study the driven translocation of polymers under time-dependent driving forces using $N$-particle Langevin dynamics simulations. We consider the force to be either sinusoidally oscillating in time or dichotomic noise with exponential correlation t
The impact of thermal fluctuations on the translocation dynamics of a polymer chain driven through a narrow pore has been investigated theoretically and by means of extensive Molecular-Dynamics (MD) simulation. The theoretical consideration is based
Using two dimensional Langevin dynamics simulations, we investigate the dynamics of polymer translocation into a fluidic channel with diameter $R$ through a nanopore under a driving force $F$. Due to the crowding effect induced by the partially trans
Using Langevin dynamics simulations, we investigate the dynamics of chaperone-assisted translocation of a flexible polymer through a nanopore. We find that increasing the binding energy $epsilon$ between the chaperone and the chain and the chaperone
We present a theoretical argument to derive a scaling law between the mean translocation time $tau$ and the chain length $N$ for driven polymer translocation. This scaling law explicitly takes into account the pore-polymer interactions, which appear