Van der Waals-Zeeman Colloquium
Thursday, 4 June 2009, 16:00
Memory effects in polymer dynamics: translocation, adsorption/desorption and melts
A strained polymer molecule relaxes its strain very slowly --- long structural correlation times are so typical of them. These long correlation times manifest themselves in the dynamical properties of polymers, such as their diffusion coefficients, viscosities etc. In this talk I will first show that the local strain in single polymers relaxes as a power-law in time. For various single-molecule experiments of recent intense interest, namely for polymer translocation (how long does it take for a polymer to pass through a narrow pore in a membrane) and for polymer adsorption/desorption, I will then demonstrate the "universality" of the strain relaxation exponents, as they dictate the experimental time-scales. Time permitting, I will then move on to the dynamics of polymer melts, a strongly many-body problem; and show that the structural correlation behaviour becomes stretched exponentials in time. This will be a peek into the ongoing work on the scaling of the viscosity exponent of polymer melts, the major unsolved problem of polymer physics in the last four decades.