Photoinduced Reorientation and Multiple Optical Data Storage in Photo-Cross-Linkable Liquid Crystalline Copolymer Films Using 405 nm Light

Abstract

New polymethacrylate liquid crystalline copolymers, which are comprised of photo-cross-linkable 4-(4-methoxycinnamoyloxy)biphenyl (MCB) and photosensitizing 4-nitrobiphenyl (NB) or 4-nitrophenyl (NP) side groups, were synthesized. The irradiation with linearly polarized (LP) 405 nm light was performed to investigate the photoinduced reorientation behavior of the thin films. On the basis of the polarization-preserved excited energy transfer from the photosensitizing groups to the MCB groups, a photoinduced optical anisotropy due to the axis-selective photoreaction of the MCB groups accompanied the photoreaction of the film. In all cases, annealing the film reversely amplified the photoinduced optical anisotropy and an in-plane order parameter greater than 0.7 was achieved for the NB-containing copolymer films. The axis-selectivity of the photoabsorption of the photosensitizing groups and the effective energy transfer played important roles in generating the large photoinduced optical anisotropy and the effective thermal enhancement. Finally, it was demonstrated that the orientation direction of the mesogenic side groups controlled the multiple optical information storage in a thin film.

Liquid crystals for holographic optical data storage

“…Although there are many nonazobenzene materials used for optical data storage, 1 we highlight a material capable of optical recording at 405 nm, which may be important since the advent of the Blu-ray technology. Kawatsuki et al 47 have recently reported the first example of multiple optical data storage using linearly polarised 405 nm laser light in a polymethacrylate liquid crystalline polymer (7), comprising photo-cross-linkable 4-(4methoxycinnamoyloxy)biphenyl (MCB) and photosensitising 4-nitrobiphenyl or 4-nitrophenyl side groups. The liquid crystal nature of the material allows the axis-selective photoreaction of the MCB side groups to generate the photoinduced optical anisotropy of the film, while a thermal treatment enhances the molecular orientation along the photocross-linked anchors parallel to the polarization direction of the linearly polarised light.…”

Poly(N‐vinylimidazole) based hydrogen bonded side chain liquid crystalline polymer

“…Recently, side chain liquid crystalline polymers (SCLCPs), which combine the unique properties of low‐molar mass liquid crystals and polymers, have been the subject of intensive research mainly due to their interesting electrical and optical properties which makes them good candidates for applications in microelectronic devices ranging from optical data storage1–4 and nonlinear optics5–8 to being the stationary phase in gas chromatography9, 10 and high performance liquid chromatography 11, 12. Side chain liquid‐crystalline polymers (LCPs) are usually prepared by covalently linking rigid mesogens to a polymer backbone through flexible spacers.…”

Спектральная Фотосенсибилизация Оптической Анизотропии В Твердотельных Пленках Поли(винилциннамата)

“…В качестве такого альтерна-тивного решения в [14][15][16][17][18] впервые были исследованы фотосшивающиеся ЖК полимеры с фотореактивными ЖК мезогенными циннамоильными и бифенильными группами в боковой цепи, в том числе при двухфотонной сенсибилизации [19]. Было установлено, что сенсиби-лизированная ФИА в таких полимерах не только тер-мически устойчива, но даже усиливается при действии повышенных температур.…”