Cross-Linking Degree Modulated Highly Sensitive Photopolymer for Holographic Data Storage by Introducing 1,3,5,7-Tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane

Abstract

Herein, via introducing 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane (V4D4) cross-linker, we dramatically improved the holographic properties of phenanthraquinone (PQ) doped poly(methyl methacrylate) (PMMA) photopolymer with high sensitivity of 0.92 cm J −1 , high diffraction efficiency ∼ 73%, and insignificant volume shrinkage ∼ 0.35% for holographic data storage, respectively. Cross-linked V4D4-PMMA macromolecules here dramatically enhance the photosensitivity about 3.4 times and diffraction efficiency more than 55%. Further analysis reveals that V4D4 obviously changed the molecular structure by cross-linking reaction with PMMA chain to be a 3D cross-linking macromolecule. And the residual vinyl groups of V4D4-PMMA dramatically accelerated the photoreaction progress, and an hexatomic ring structured −C−O−C− bond formed between V4D4 and PQ. However, further analysis demonstrates that there is a strong positive correlation between the diffraction efficiency and photosensitivity with the degree of cross-linking in V4D4-PMMA. Moreover, the cross-linked V4D4-PMMA structure enhances the mechanical properties slightly and so suppressed the volume shrinkage of PQ/PMMA during photoreaction. Finally, the microphysical thermal-reaction and photoreaction mechanisms of V4D4 on the holographic performance of PQ/PMMA were investigated. Therefore, V4D4-PMMA/PQ macromolecular photopolymer appeared to be promising for promoting the development of high-sensitivity holographic data storage.