The semicrystalline morphology of the semiflexible smectic polyester [OCOPhOCOPhCOOPhCOO(CH 2 ) 7 ] n is investigated by high-resolution electron microscopy. Images combining diffraction and phase contrast allow simultaneous visualization of the mesomorphic and semicrystalline phases. A smectic C 2 mesophase is confirmed by electron diffraction of quenched (noncrystalline) specimens. A new disordered-uniaxial model is developed to evaluate the molecular tilt in smectic mesophases in which the layers rather than the molecules are aligned. Biaxial symmetry for small selected areas (<200 nm) and uniaxial symmetry, about the layer normal, for larger areas requires extended polymer chains to be twisted and entangled around one another