We describe the characterization, ferroelectric phase stability and polarization switching in strain-free assemblies of PbZr0.3Ti0.7O3 (PZT) nanostructures. The 3dimensionally ordered macroporous structures present uniquely large areas and volumes of PZT where the microstructure is spatially modulated and the composition is homogeneous. Variable temperature powder X-ray diffraction (XRD) studie...