ИСТИНА

The diagram of states of a single multiblock copolymer chain consisting of flexible and semiflexible blocks with regular sequence of these blocks in bulk are studied by means of Monte Carlo method. We use Wang-Landau sampling and bond fluctuation lattice model. Monomer units of both kinds (flexible and semiflexible) are equivalent in the sense of the volume interaction potential. We vary the length of the blocks and the value of stiffness parameter. We investigate chain lengths 64 and 256 monomer units. We present our data on different non-trivial heterogeneous globular morphologies which we have obtained in our model for different values of the block length and the stiffness parameter. We demonstrate that the collapse can occur in one or in two stages for chain length 64 monomer units depending on the values of both these parameters and in two stages for chain length 256 monomer units. For both chain length for short block length the semiflexible monomer units form the core and flexible ones – the shell of a globule, for long block length – vice versa. Transition between these two regimes depends on stiffness – for larger stiffness it occurs at larger block length. For chain of 64 monomer units for short blocks there are two transitions - between solid globule and liquid globule and between liquid globule and coil. For long blocks with increasing stiffness we observe only a single transition – between the dumb-bell-like globule (semiflexible blocks form a cylinder-like core, and the flexible blocks form two domains at both ends of such a cylinder) or Saturn-like globule (the flexible blocks form a spherical core of a globule while the semiflexible blocks are located on the surface and wrap around this core) globule and coil. For chain of 256 monomer units we observe two stages transition. The transition occurs during the liquid globule stage for all block length.