Highly Photosensitive Phenanthrenequinone-doped Poly(methyl methacrylate) Photopolymers in Big Data

After several centuries of development, photosensitive materials are being widely used in photography and videography. However, a material that possesses low shrinkage and can ensure high sensitivity is still elusive. Therefore, we have developed and designed a photosensitive material that maintains high sensitivity while exhibiting low shrinkage and excellent stability to address the growing demand for high-speed holographic data storage system in the big data era. A novel material, thiol-ene-phenanthrenequinone (PQ)-doped poly(methyl methacrylate) (PMMA), was developed by incorporating pentaerythritol tetra(3-mercaptopropionate) (PETMP) into a cross-linked PMMA network. Compared with traditional PQ/PMMA (~0.55 cm·J −1 ), the improved formulation demonstrated a four-fold increase in photosensitivity (~2.54 cm·J −1 ) and a drastically reduced response time (from ~70.93 s to ~7.57 s). More importantly, the material maintained a low photo-induced shrinkage factor of ~6.6‰. Practical testing in a collinear holographic storage system confirmed the capability of the material to record a single holographic data page within 1 s and maintain a bit error rate below 1%. Microscopic characterization revealed that the enhancement mechanisms involved the thiol-ene anti-Markovnikov addition reaction during exposure and a retardation effect during thermal polymerization, which increased the residual monomer concentration (from ~5% to ~11%) available for photochemical reactions. Furthermore, the cross-linked network improved the thermal stability of the PMMA matrix, evidenced by the increased decomposition temperature and glass transition temperature (T g ), without adversely affecting the volume stability. These findings indicate that the thiol-ene-PQ/PMMA material is a highly promising candidate for enabling fast high-density holographic data storage, potentially meeting the requirements of future servo-based collinear storage systems.