The persistence length is a basic mechanical property quantifying the bending stiffness of a polymer.
Informally, for pieces of the polymer that are shorter than the persistence length, the molecule behaves like a rigid rod, while for pieces of the polymer that are much longer than the persistence length, the properties can only be described statistically, like a three-dimensional random walk.
For charged polymers the persistence length depends on the surrounding salt concentration due to electrostatic screening.
The persistence length of a charged polymer is described by the OSF (Odijk, Skolnick and Fixman) model.
m (taking in consideration a Young modulus of 5 GPa and a radius of 1 mm).
If you choose two points on this flexible cord (imagine a piece of cooked spaghetti that you've just tossed on your plate) that are very far apart, however, the tangent to the cords at those locations will likely be pointing in different directions (i.e. the angles will be uncorrelated).
For the case of a single molecule of DNA the persistence length can be measured using optical tweezers and atomic force microscopy.
[12][13] Persistence length measurement of single stranded DNA is viable by various tools.
[14][15] The recent attempts to obtain persistence length is combination of fluorescence correlation spectroscopy (FCS) with HYDRO program.
The polymer property was adjusted to find the optimal persistence length.