Force-extension curves for broken-rod macromolecules: Dramatic effects of different probing methods for two and three rods.
We study force-extension curves of a single semiflexible chain consisting of several rigid rods connected by flexible spacers. The atomic force microscopy and laser optical or magnetic tweezers apparatus stretching these rod-coil macromolecules are discussed. In addition, the stretching by external isotropic force is analyzed. The main attention is focused on computer simulation and analytical results. We demonstrate that the force-extension curves for rod-coil chains composed of two or three rods of equal length differ not only quantitatively but also qualitatively in different probe methods. These curves have an anomalous shape for a chain of two rods. End-to-end distributions of rod-coil chains are calculated by Monte Carlo method and compared with analytical equations. The influence of the spacer's length on the force-extension curves in different probe methods is analyzed. The results can be useful for interpreting experiments on the stretching of rod-coil block-copolymers.
Faculty of Physics, Moscow State University, 119991 Moscow, Russia.
A V
AV
Alexeev
Faculty of Physics, Moscow State University, 119991 Moscow, Russia.
D V
DV
Maltseva
Faculty of Physics, Moscow State University, 119991 Moscow, Russia.
V A
VA
Ivanov
Department of Physics, American University of Beirut, P.O. Box 11-0236, Beirut 1107 2020, Lebanon.
L I
LI
Klushin
Chemical-Pharmaceutical Academy, Prof. Popova 14, 197022 St. Petersburg, Russia.
A M
AM
Skvortsov
D046911:Macromolecular Substances / Q000737:chemistry*; D060328:Magnetic Phenomena; D055595:Mechanical Phenomena; D008958:Models, Molecular; D008968:Molecular Conformation; D009010:Monte Carlo Method; D011336:Probability
D046911:Macromolecular Substances