Curvature-directed Crystallization of Polymer Dielectrics in Nanopores

Abstract

The formation of isotactic poly(propylene) (iPP) and polycarbonate (PC) nanowires of tunable diameter was demonstrated by melt-wetting the polymer into nanoporous anodic alumina. The crystallization process was analyzed using differential scanning calorimetry. A transition from hetero- to homogeneous crystallization was observed for iPP as the pore diameter decreased. Also, the Avrami exponent decreased as the pore diameter decreased, indicating preferential 1-D crystallization for diameters of 40 nm or less. X-ray diffraction studies showed that the polymer chains crystallize into the α-phase and that they preferentially orient along the a- and b-axis, perpendicular to the pore wall. Directed crystallization of iPP may enhance the materials electrical and mechanical properties.