High Performance Graded Rainbow Holograms via Two-Stage Sequential Orthogonal Thiol鈥揅lick Chemistry

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• 作者：Haiyan Peng ; Devatha P. Nair ; Benjamin A. Kowalski ; Weixian Xi ; Tao Gong ; Chen Wang ; Michael Cole ; Neil B. Cramer ; Xiaolin Xie ; Robert R. McLeod ; Christopher N. Bowman
• 刊名：Macromolecules
• 出版年：2014
• 出版时间：April 8, 2014
• 年：2014
• 卷：47
• 期：7
• 页码：2306-2315
• 全文大小：502K
• 年卷期：v.47,no.7(April 8, 2014)
• ISSN：1520-5835

文摘

Orthogonal, sequential 鈥渃lick鈥?reactions were implemented to yield novel polymeric substrates with the ability to record holographic data. The base-catalyzed thiol鈥揳crylate Michael 鈥渃lick鈥?reaction was implemented to yield a writable, stage 1 polymeric substrate with glass transition temperatures (T_g) ranging from 0 to 鈭?6 掳C and rubbery storage moduli (E鈥? from 11.1 to 0.3 MPa. The loosely cross-linked matrix also contained a novel high refractive index monomer 9-(2,3-bis(allyloxy)propyl)-9H-carbazole (BAPC) that did not participate in the thiol鈥揗ichael reaction but allowed for large index gradients to be developed within the network upon subsequent exposure to coherent laser beams and initiation of the radical-mediated thiol鈥揺ne reaction. The holographic gratings were recorded with 96% diffraction efficiency and ca. 2.4 cm/mJ of light sensitivity in 2 s under a 405 nm exposure with an intensity of 20 mW/cm². Subsequent to pattern formation, via a thiol鈥揳llyl radical 鈥渃lick鈥?photopolymerization initiated by flood illumination of the sample, holographic materials with high T_g, high modulus, diffraction efficiency as high as 82%, and refractive index modulation of 0.004 were obtained. Graded rainbow holograms that displayed colors from blue to red at a single viewing angle were readily formed through this new technique.