Optical anisotropy of cellulose

Optical Anisotropy of Cellulose Esters and Its Application to Optical Functional Films... 

Yamaguchi, M., Iwasaki, T., Okada, K., and Okamoto, K (2009). Control of optical anisotropy of cellulose esters and their blends with... 

Optical Anisotropy of Solution-Cast Cellulose Ester Films... 

Extensive studies on the optical anisotropy of hydrated cellulosic gel in relation to deformation have been reported by Kratky " and by Hermanns. "" Kratky studied the deformation mechanism of fibrous materials by means of X-ray diffraction and birefringence, and postulated two kinds of deformation models for the swollen gel, in order to explain the orientation mechanism of the structural units in terms of the orientation distribution (but not in terms of the average degree of orientation of the structural units). Hermanns carried out studies on the same lines as Kratky, and introduced one of the orientation factors as a measure of the average degree of orientation. ... 

Like cellulose, nitrocellulose demonstrates optical anisotropy (double refraction) which is regarded as one of the facts confirming the microcrystalline structure of the substance. A relationship between this property of nitrocellulose and the nitrogen content has been discovered by Ambronn [127] who studied the double refraction of cellulose. Differences in the refractive index for rays of different wavelengths in two directions at right angle are of the order —0.50 x 10-3 to +2.8 x 10"3 (Table 60). 

Before and after the works described above, contributions to the design and fabrication of similar multicomponent films or gels of cholesteric character, mainly based on HPC, EC, or their derivatives were also made [202, 219-224], Some of these [219,220,224] dealt with shear-deformed network systems preserving a unique banded structure, so that the disappearance and recovery of the optical anisotropy could be controlled thermo-reversibly. Special mention should be made of the successful preparation of two novel classes of solid materials maintaining cholesteric liquid-crystalline order. One consists of essentially pure cellulose only, and the other is a ceramic silica with an imprint of cellulosic chiral mesomorphy. 

Optical Anisotropy and Structui% of Polymer Chains Ladder Polysiloxanes and Cellulose Esters and Ethers... 

However, some stretched films of cellulose esters are known to show extraordinary wavelength dispersion. In this chapter, wavelength dispersion of in-plane and out-of-plane birefringences for cellulose esters is mentioned in detail after a brief introduction on the concept of controlling the optical anisotropy. The molecular orientation and the birefringence of a solution-cast film for CTA are explained. Finally, an advanced method to obtain the extraordinary dispersion of the in-plane and out-of-plane birefringences is proposed. 

Songsurang, K., Miyagawa, A., Manaf, M. E. A., Phulkerd, R, Nobukawa, S., and Yamaguchi, M. (2013). Optical anisotropy in solution-cast film of cellulose triacetate. Cellulose. 20, 83-96. 

Nobukawa, S., Hayashi, H., Shimada, H., Kiyama, A., Yoshimura, H., Tachikawa, Y, and Yamaguchi, M. (2014). Strong orientation correlation and optical anisotropy in blend of cellulose ester and poly(ethylene 2,6-naphthalate) oligomer, I. Annl. Polvm. Sci.. 131, 40570. 

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