Viscoelasticity of a stretched polymer chain with ends exposed to a constant force |
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Authors: | N K Balabaev I P Borodin T I Borodina T N Khazanovich |
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Institution: | 1.Institute of Mathematical Problems of Biology,Russian Academy of Sciences,Pushchino, Moscow oblast,Russia;2.Kostroma State Technological University,Kostroma,Russia |
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Abstract: | The viscoelasticity of a stretched polymer chain with its end particles exposed to oppositely acting forces is studied via
collisional molecular dynamics and analytically. A simple model according to which a polymer molecule is a chain of particles
linked through freely jointed elastic bonds is adopted. The analytical theory is in good agreement with the results of the
computer simulation of time correlation functions in the range of large-scale motions of a polymer molecule. It is found that
the decay of correlation functions K
αβμν of fluctuations of the microscopic stress tensor of a chain, K
zzzz, K
zαzα
, = K
zαzα
, (α = x, y; z is the axis along which the forces act), is slowed down, and their value increases relative to the respective correlation
functions of a chain with fixed ends. The greater the force, the higher this difference. The correlation functions that are
transverse with respect to the z axis do not differ from those for chains with fixed ends. The results show that, in the calculation of time correlation functions
of strongly stretched polymer chains, different statistical ensembles are not equivalent; this must be taken into account
in the dynamic theories of heavily deformed polymers. |
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Keywords: | |
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