Three-Dimensional Molecular Orientation Imaging of a Semicrystalline Polymer Film under Shear Deformation

The 3D molecular orientations of polymer chains are imaged and compared for a quiescent spherulite region and a shear-deformed region of a semicrystalline poly(epsilon-caprolactone)film. To acquire the images of 3D orientation, we used a newlydeveloped hyperspectral imaging method based on the orthogonal-pair polarization IR (OPPIR) analysis. Polymer chains inspherulites are azimuthally aligned perpendicular to the crystalgrowth direction and axially tilted from thefilm normal direction.By contrast, polymer chains in a sheared region are azimuthallyaligned along the shear direction but axially tilted from the sheardirection. The unexpected out-of-plane tilted orientation indicatesthat orientational relaxation followed shear deformation andoccurred predominantly in the out-of-plane direction. Further-more, incorporating peak deconvolution into the OPPIR analysis shows that the crystalline and amorphous chains are orientedaligned at different angles, possibly due to different orientational relaxation between the two chain configurations.

Automated summary

In this study, the 3D molecular orientations of polymer chains in both a quiescent spherulite region and a shear-deformed region of a semicrystalline poly(epsilon-caprolactone) film were imaged and compared. The results showed that the polymer chains in both regions were aligned in the azimuthal direction, but there was axial tilt. Additionally, there were differences in molecular orientation between different chain configurations.