Coil-to-globule transitions of homopolymers and multiblock copolymers.

We study the coil-to-globule transitions of both homopolymers and multiblock copolymers using integrated tempering sampling method, which is a newly proposed enhanced sampling method that can efficiently sample the energy space with low computational costs. For homopolymers, the coil-to-globule structure transition temperatures (Ttr) are identified by the radius of gyration of the chain. The transition temperature shows a primary scaling dependence on the chain length (N) with Ttr ∼ N(-1/2). For multiblock copolymers, the coil-to-globule transition can be identified as first order, depending on the block size and the difference in attractive interactions of blocks. The influence of mutating a small portion of strongly attractive blocks to weakly attractive blocks on the coil-to-globule transition is found to be related to the position of the mutation.