Hole structures of polymers and zeolites probed by two-dimensional angular correlation of annihilation radiation

Abstract

The two-dimensional angular correlation of annihilation radiation (2D-ACAR) technique has been developed to measure the hole structure of stretched and oriented polymers. The determination of polymer hole structure is demonstrated in a stretched semi-crystalline polyaryl-ether-ether-ketone (PEEK) sample. The atomic scale anisotropy is found to be consistent with the macroscopic scale stretch ratio. Applications of the 2D-ACAR method to image the three-dimensional hole, free-volume, and cavity structures of molecular systems are discussed.