Equilibrium and kinetics at the coil-to-globule transition of star and comb heteropolymers in infinitely dilute solutions

By means of continuous space Monte Carlo simulation we study conformational structures formed by star and comb heteropolymers during kinetics of folding from the coil to the globule, as well as the corresponding equilibrium states on going from the good to the poor solution. Particular examples of combs with hydrophobic backbone and hydrophilic side-groups (and vice versa), as well as stars with flexible and semi-stiff arms are studied. It is interesting to note that star-like conformations naturally appear for a comb polymer with a strongly hydrophobic backbone. We emphasise the crucial difference in the spatial distribution of hydrophobic and hydrophilic monomers within the globular states for the above mentioned two types of combs. In case of stars, the non-equilibrium states during kinetics of the coil-to-globule transition correspond to formation of localised pearls within flexible arms, whereas semi-stiff arms prefer to join with each other remaining essentially extended. These studies present natural extension of our previous works on the equilibrium and kinetic properties of linear and ring heteropolymers based on the Gaussian self-consistent method and lattice Monte Carlo technique. However, in studying polymers with more nontrivial topology continuous space simulation has some essential advantages.

E.G. Timoshenko, Yu.A. Kuznetsov · 2001