Response of a jammed system of telechelic associating polymers to an external stress

Includes bibliographical references (p. 43)Solutions of self associating telechelic polymers are part of a unique classification known as viscoelastic materials. At low temperatures the end groups of these polymers connect and a network forms. Viscous response (sol) at high temperature gives rise to elastic deformation (gel) at low temperatures. When the gel is subjected to a constant stress, it will flow; however below a critical stress, it will exhibit a slow creep. This is called a jammed state. In this state the gel alternates between moving with and against the direction of the stress. If the dynamics are chaotic then these fluctuations are described by the Gallavotti-Cohen Steady State Fluctuation Relation (SSFR). This has been verified for other viscoelastic systems, but not yet in a polymeric gel. My research aims to investigate if the relation holds in a polymeric gel as well. To this end I use data sets generated by a computer simulation developed by Dr. Arlette Baljon, based on the Kremer-Grest bead spring model, for a system of telechelic polymers in solution. Using the linear least squares fit of the systems position data we were able to determine the shear-rate of the system and identify the stresses for which the gel is jammed. We found the fluctuations of the system are large. We verified that their probability distribution functions behave as predicted by the SSFR. We also compute the effective temperature as an effect of the kinetic driving of the system