THE DIAGONAL BOND METHOD - A NEW LATTICE POLYMER MODEL FOR SIMULATIONSTUDY OF BLOCK-COPOLYMERS

A new lattice model for Monte Carlo simulations of dense polymer melts , developed in the spirit of Verdier-Stockmayer algorithm on square an d simple cubic lattices, is presented. By introducing diagonals of squ ares and cubes as bonds, the lattice model acquires a large number of configurations and wiggling local moves. While it maintains the exclud ed Volume interactions of monomers, it allows bond crossings and phant om moves, which result in a high mobility of polymers. For an applicat ion, we carry out simulations of symmetric A-B block copolymer melts a nd observe a first-order transition. We also show the stretching of th e chains, namely, the non-Gaussian character, as a function of tempera ture. A quicker evolution towards thermal equilibrium enables us to fo rm an ordered tricontinuous double-diamond (OTDD) phase for linear A-B -C triblock copolymers and a new cylindrical phase for star A-B-C trib lock copolymers. (C) 1996 American Institute of Physics.