Effects of electron irradiation on structure and bonding of polymer spherulite thin films

Abstract

We report the detailed beam effects in PE, PCL, and P3HT spherulite thin films, including both structure and chemical bonding evolution detected from quantitative electron diffraction and spectroscopy. Both amorphization and mass loss from electron beam irradiation have been clearly identified, most of which can be suppressed effectively by cryo-protection. The initial dominant beam effect in PE and PCL thin films is the radiolysis of C–H bonds, leading to both amorphization and the formation of unsaturated polyenyl groups that further cause lattice expansion. When the samples become mostly amorphous, the mass loss effect becomes prevailing. On the other hand, P3HT exhibits an intriguing two-stage damage process with the side-chain ordering destroyed prior to the π-stacking ordering. Our results not only shed light on the detailed beam effects on structure and chemical bonding in the three polymers, but also demonstrate a powerful approach to quantitatively analyze these effects in other organic solids.