Dynamics of conformational transitions in polymers.

Conformational transitions in polymers involve large angle rotations about bonds. The process must proceed in a way that does not require gross movements of the macromolecules. The dynamics have been investigated by computer simulation and kinetic theory. The rate-determining step in the transition is found to occur in a mode which is kept local by distortion of nearby parts of the molecule. One especially important type of cooperativity, crank-like counterrotation of second-neighbor bonds, is identified. Experiments which provide evidence about the dynamics of conformational transitions are discussed.