Examination of Size-Induced Ferroelectric Phase Transitions in Template Synthesized PbTiO₃ Nanotubes and Nanofibers

Here we report on the application of sol−gel template synthesis to the investigation of size-induced ferroelectric phase transitions in lead titanate (PbTiO 3 ) nanotubes and nanofibers. A 0.8 M chelate sol−gel, made from titanium(IV) tertabutoxide and lead(II) trihydrate acetate, was applied to two different templates. Nanotubes were formed within 200-nm-pore Whatman anodisc aluminum oxide membranes, and nanofibers were prepared using 50-, 100-, and 200-nm Whatman track-etched polycarbonate membranes. Transmission electron microscopy images revealed that the tubes comprised grains of ≤20 nm and the fibers comprised individual grains ≤200 nm in width when a 200-nm pore size template is used. An examination of how the grain/crystallite size and aspect ratio of one-dimensional morphologies affect the ferroelectric phase transition was monitored through the comparison of bulk powders and the nanostructured materials using electron diffraction, X-ray diffraction, Raman spectroscopy, and differential scanning calorimetry.