Epitaxial growth of polyethylene oxide atop muscovite mica

Semi-crystalline polymers confined to nanoscale dimensions often crystallize in unexpected ways vastly different from that of bulk crystallization. The crystallization of ultrathin (< 100 nm) films atop solid surfaces is one example, in which the interaction of polymer chains with the underlying substrate is vital in determining the crystallization kinetics and film morphology. Additionally, geometric matching at the molecular scale between the polymer and substrate may induce epitaxial growth. In this work, we deposit ultrathin films of polyethylene oxide atop muscovite mica by matrix-assisted pulsed laser evaporation. We demonstrate an epitaxial relationship between needle-like polymer crystals and the substrate. Mechanisms of nucleation and growth of the epitaxial crystals are discussed.