Birefringence of cellulose: review, measurement techniques, dispersion models, biomedical applications and future perspectives

Cellulose, the basic biopolymer of plants, has unique optical characteristics due to its inherent birefringence. In this review, we summarize reported birefringence values for cellulose from the literature and describe its measurement techniques, including ellipsometry, interferometry, spectrophotometry and photothermometry. We also discuss the main dispersion models that have been proposed to explain the wavelength dependence of cellulose birefringence. Furthermore, we outline the diverse applications of cellulose birefringence, with a particular focus on biomedicine. Finally, we discuss the future prospects for cellulose birefringence. Overall, this review provides valuable insights into the basic research and practical application of cellulose birefringence and will stimulate new research and innovation in various fields.