Monte Carlo simulations of lattice model of branched polymer chains were performed. The object of this simulation was a uniform star-branched polymer of equal length which was confined to a simple cubic lattice and consisted of f ϭ3 arms of equal length. An efficient dynamic Monte Carlo algorithm was used to study the motion of a single athermal chain. Simulations were performed for star-branched chains with and without the excluded volume and for linear polymers in the same range of molecular weights. The maximum total chain length was 800 beads in both cases. The detailed comparison of static and dynamic properties of star-branched and linear polymers was made via the analysis of some new correlation functions as well as widely used parameters. The differences in the motion of star-branched and linear chains were described and discussed.

In this study, we investigated the process of random sequential adsorption of stiff and flexible polymer chains on a two-dimensional square lattice. The polymer chains were represented by sequence of lattice points forming needles, T shapes, and crosses as well as flexible linear chains and star-branched chains consisted of three and four arms. The Monte Carlo method was employed to generate the model systems. The percolation threshold and the jamming threshold were determined for all systems under consideration. The influence of the chain length and the chain architecture on both thresholds was calculated and discussed. The changes in the ordering of the system were also studied.

We studied the structure of a polypeptide model by means of the Monte Carlo method. The model chain consisting of two kinds of residues (hydrophobic and hydrophilic) was confined on the (310) hybrid lattice. The residues interacted with the long‐range contact potential. The short‐range potential was also used by introducing the preferences of conformations corresponding to the helical structure. Simulations of the coil‐to‐globule collapse were done by an annealing process starting from high‐temperature structures and then gradual cooling of the system. The parameters describing the behavior of the system were monitored. It has been found that in a case of a helical pattern –HHPPHPP‐ the collapsed chains consisted of helical fragments. The resulting structures were formed in such way that the polar residues were located in the outer shell of the molecule since the hydrophobic residues filled the inner part of molecule. The results showed that the proper balance between the magnitude of the potentials used in a model is important and its influence on final structures of molecules was discussed. © 2000 John Wiley & Sons, Inc. Biopoly 54: 262–272, 2000

On lyotropic behavior of molecular bottle-brushes: A Monte Carlo computer simulation study

The lattice approximation of a heteropolymer chain as a model of a single polypeptide was used in the computer simulation. The residues of a model polypeptide were represented by the chain of alpha-carbons located on a very flexible [310] lattice. The force field that mimic the intramolecular interactions contained the long-range contact potential between the residues and the local preferences in forming helical structures. The chain consisted of two types of residues that had different hydrophobicity. The simulations were performed by means of the Replica Exchange Monte Carlo method combined with the Histogram method. The series of simulations were carried out to investigate the influence of both components of the force field on the transition temperature and the characteristics of the coil-to-globule transition. The properties of low-temperature ordered structures were determined. The thermodynamical description of the model chain was also given. The phase transition was found to be sharp and cooperative for longer chains and strong helical potential. The collapsed globule contained the strongly hydrophobic residues inside the globule while the remaining residues were mainly located close to the globule surface.