IODINE-INDUCED UNCOILING OF POLYISOPRENE RANDOM COILS IN SOLUTION

Recently, we demonstrated that conjugated sequences of unsaturated dou ble bonds can be introduced into 1,4-polyisoprene backbone through con jugation reactions induced by iodine [1]. Here, we report a structural investigation on the conjugated polyisoprene chains in solution by me ans of small angle X-ray scattering (SAXS). The SAXS results indicate a conformational transition from a random coil, characteristic of the pristine polyisoprene chains in solution [2], to a rod-like structure by uncoiling of the macromolecular coils due to a remarkable increase in chain rigidity associated with the formation of rigid conjugated se quences via the I2-induced conjugation reaction.