Localization of Semiflexible Filaments in a Random Potential.

Semiflexible filaments, such as F-actin, can be cross linked into complex networks including those found in in vitro experiments and in the cytoskeleton of living cells. Recent work on transiently cross linked semiflexible gels [K.W. Mueller et al., PRL 112, 238102 (2014).] suggests that filaments are typically quenched during network formation into highly stressed states. In order
to better understand these quenched gels, we consider the problem of a single semiflexible filament interacting with a random potential at finite temperature. We examine the system analytically using a saddle-point approximation and with numerical simulations to explore the distribution of pinned filament configurations as a function both filament persistence length and spatial correlations of the quenched potential.
We obtain a theoretical result prediction a continuous crossover from a ''floating phase'' in which the stiff polymer interacts weakly with the potential and remains essentially straight to a strongly adhered phase in which the stiff potential curves to follow the
local minima of the potential.