Epitaxially crystallized polyethylene exhibiting near-equilibrium melting temperatures*

The morphology and orientation of polymer crystals are important factors which determine the performance of thin-film, polymer-based technologies such as organic electronic devices and gas separation membranes. Here, we utilize polymer-substrate epitaxy to achieve a highly oriented crystalline morphology during thin-film processing. To accomplish this, we employ matrix-assisted pulsed laser evaporation (MAPLE), a slow physical vapor deposition process, to deposit linear polyethylene epitaxially atop a graphene substrate. Via MAPLE, we demonstrate the ability to achieve a film morphology comprised of well-aligned, edge-on crystalline lamellae. Furthermore, we show that MAPLE can be exploited to grow crystalline lamellae composed entirely of extended polymer chains which exhibit a near-equilibrium melting temperature. Our study demonstrates that MAPLE, as a bottom-up approach, can deposit polymer thin films with improved control over crystalline morphology.