Highly oriented ultrathin polyethylene (PE) films were prepared by a melt-draw technique. Transmission electron microscopy study on the obtained ultrathin films indicates that the melt drawn PE thin films consist of highly oriented edge-on lamellae aligned perpendicular to the drawing direction. Electron diffraction confirms that the PE chains in crystalline phase are highly oriented in film plane along the drawing direction, while only a random orientation of the crystallographic a-and b-axes can be described through electron diffraction. The IR results on the melt-drawn ultrathin PE films demonstrate that the PE molecular chains in both crystalline and amorphous phases of the melt drawn thin films are well oriented along the drawing direction. Moreover, the IR results indicate that in the crystalline phase, the crystallographic b-axis tend to lie in the thin film plane, while in the amorphous phase, the skeleton plane of some local chains prefers to parallel the film plane. The alignment of b-axis of PE crystals in ultrathin films originates from the fact that the b-axis is the fastest growth direction of the PE crystals.The technological significance of the highly oriented polymer materials derives from the fact that the properties of the oriented materials may exceed those of their isotropic species by general orders of magnitude. For example, the stiffness and strength of highly oriented crystalline polymers [1,2] can increase to a factor of 100 compared with their non-oriented counterparts. Therefore, highly oriented polymer materials have received considerable interest in the past few decades. Generally, in most polymer processing operations, such as fiber spinning and extrusion, etc., the molten polymer is exposed to varying levels of flow fields, which encourage the development of high degree of orientation. For these products, wide-and small-angle X-ray scatterings are frequently used for characterizing their morphological information. Moreover, skillful experimental techniques for producing highly oriented ultrathin polymer films, such as drawing from the thin polymer melts [3] and frictions from the solid blocks [4,5] , enable us to produce thin films of tens nanometers, which are ideal for real space morphology as well as electron diffraction studies on themselves, as substrate inducing crystallization of other polymers. Consequently, a large number of investigations have been done to characterize the morphological and orientational features of oriented thin polymer films. It should be pointed out that, however, the information about chain orientation given by electron and X-ray diffractions is only related to the chains in crystalline region of the semicrystalline polymers. To our knowledge, the alignment of the chains in the amorphous areas of the highly oriented thin films is hardly concerned so far.Infrared spectroscopy (IR) is sensitive to both chain conformation and molecular environment. Fourier transform infrared spectroscopy combining with polarized infrared beam is a powerful tool to probe ...