ABSTRACT

The real world of polymer translocation is far more complex than the rudimentary physical models developed in the preceding chapters. The complexity of the phenomenon arises due to particular combinations of entropic contributions from polymer conformations and energetic contributions from polymer-pore interactions that are specific to the particular translocation systems. The spirit of the description of translocation developed so far is along the direction of identifying the most general universal model, which forms the basic skeleton of the process, with the entropy and energy contributions being parametrized. The chemical details, and the physicochemical processes in the physical vicinity of the translocation event, must be addressed in interpreting these parameters for a specified system. We shall briefly mention below a few examples of how chemical details are amplified in the observed features of polymer translocation. While the general premise of translocation processes is the sequence of capture/recognition, nucleation, and threading, these chemical details must be accounted for in quantitative descriptions. Complementary to the challenges in addressing the diversity in chemical details, there are also challenges in understanding the nonequilibrium polymer conformations particularly when the threading is much faster than the equilibration times for polymer conformations. We illustrate these issues briefly here to underline the ongoing investigations.