Shape Analysis of Energy Polydisperse Polymers

The equilibrium properties of an energy polydisperse chain, in which the interaction strengths between the monomers are drawn from a log-normal distribution, at small polydispersity value are investigated by means of computer simulations. We perform coarse-grained molecular dynamics simulations in an implicit solvent condition, and a comparative study with that of the corresponding homopolymers is carried out. In this study, we focus our attention in understanding the behavior of average instantaneous conformations, characterized through various shape parameters for both energy polydisperse and homopolymer chains as a function of temperature (T). It is found that the energy polydisperse chain has relatively low value of theta-temperature (T-theta), at which polymer assumes ideal conformation. In particular, we investigate the conformational changes across T-theta and found that for T at/above T-theta the behavior is independent of the chain type and length, whereas for T below T-theta,T- strong dependence on the chain length is observed. To understand the detailed statistics, we also compare the distributions of chain sizes as well as eigenvalues of the gyration tensor.