Form factor for distorted semi-flexible polymer chains

Abstract

The statistical presence of kinks which form defects in semi-flexible polymer chains leads to a polydispersity in the effective persistence length. The form factor of a distorted semi-flexible polymer results as an average over this persistence polydispersity. It turns out that the scattering behavior of an ensemble of distorted semi-flexible polymer chains is quite well approximated by a form factor of an undistorted chain with a R-equivalent persistence length. An apparent length polydispersity is observed for short distorted chains. The R-equivalent persistence length is significantly smaller than the innate persistence length multiplied by the fraction of regular monomers. The results are compared to related work on DNA from the literature.

The viscoelastic signature underpinning polymer deformation under shear flow

“…However, the detailed shape of the form factor can have considerable differences in the various cases listed above. While many isotropic theories exist for equilibrium [19][20][21], anisotropic scattering patterns up to now have been analyzed in mostly ad hoc fashion: fitting 1D radial cuts [6], comparing angular sector averages [9], fitting ellipses to isointensity curves [6], and fingerprinting with spherical harmonics [4]. In the present work, we develop a new approach to extract the underlying real-space structure directly from the data, not requiring any knowledge of the molecular motion.…”