Related Experiment Video
Updated: Feb 1, 2026

Terahertz Imaging and Characterization Protocol for Freshly Excised Breast Cancer Tumors
Published on: April 5, 2020
Quantitative Monitoring of Crystalline Phase Transformation and Orientation Evolution in Poly(vinylidene fluoride)
Haokun Xiao1, Maoyuan Li2, Jianjian Huang1
1National Engineering Research Center of Novel Equipment for Polymer Processing, South China University of Technology, Guangzhou 510641, China.
None:
Crystalline phase transformation and orientation evolution in crystalline polymers critically influence processing performance, yet real-time and spatially resolved characterization remains challenging. Conventional crystal characterization techniques such as infrared spectroscopy and X-ray technology provide accurate measurements but are limited by slow acquisition rates and difficulties in mapping spatial distributions. Leveraging the crystal structure sensitivity of terahertz time-domain spectroscopy (THz-TDS), this study reports a dynamic and nondestructive method for monitoring dynamic crystalline phase transformations and orientation evolution in poly(vinylidene fluoride) (PVDF) during uniaxial stretching. The THz anisotropic absorption exhibited a strong linear correlation with both the β-phase fraction and orientation parameter, indicating that THz-TDS can quantitatively capture structural anisotropy. Semiquantitative models between THz anisotropic absorption and the fraction and orientation of the crystal were developed and experimentally validated. The measured β-phase fraction showed good agreement with FTIR and 2D-WAXD results, with RMSE values of 0.019 and 0.005, respectively. THz spectral imaging further enabled the visualization of spatial distributions of both the phase content and orientation, revealing the orientation and phase evolution during stretching. Spatial mapping showed that regions of increased β-phase content and orientation coincided with the necking zone, suggesting that localized deformation during necking drives the crystalline phase transformation. This work establishes THz-TDS as a rapid, noninvasive, and distribution-resolved tool for monitoring structural evolution in crystalline polymers, with potential applications in in-line process control and polymer physics studies.
More Related Videos
Related Concept Videos
The Evidence for Evolution
Convergent Evolution
Polymer Classification: Crystallinity
Crystalline domains are the regions where polymer chains are aligned in an orderly manner and held together in proximity by intermolecular forces. For example, chains in the crystalline domains of polyethylene and nylon are bound together by van der Waals...
Eukaryotic Evolution
Contrary to the endosymbiont theory, the eukaryote-first hypothesis proposes that the simpler prokaryotic and...
Synteny and Evolution
Around 80 million years ago, the human and mice lineages diverged from the common ancestor. During the course of evolution, the ancestral...
Bacterial Transformation
Griffith made an unexpected discovery when he killed the pathogenic strain and mixed its remains with the live, non-pathogenic strain. Not only did the mixture kill host mice, but it also contained living pathogenic bacteria that...

