Thiol-Ene Photopolymerization Enhances Liquid Crystal Ordering and Structural Regularity in Holographic Polymer Nanocomposites: A Coupled DPD-FDTD Simulation

W Wei and S Li and XP Zhou and HY Peng and XL Xie, MACROMOLECULES, 58, 2459-2471 (2025).

DOI: 10.1021/acs.macromol.4c02287

Holographic polymer nanocomposites comprising liquid crystals (LCs), which are basically formulated by periodic photopolymerization-induced phase separation under coherent lasers, exhibit significant application value in a myriad of high-tech fields such as augmented reality (AR)/virtual reality (VR), 3D displays, advanced anticounterfeiting, and holographic sensing. Herein, by coupling the dissipative particle dynamics (DPD) simulation in the mesoscale and finite-difference time- domain (FDTD) simulation in the macroscale, we disclose that the thiol- ene click polymerization can lead to greater LC ordering in holographic polymer nanocomposites. Besides, compared to the thiol-acrylate polymerization system, step-growth polymerization dominates in the thiol-ene click polymerization system, giving rise to more regular phase separation structures with higher polymer density and lower interfacial roughness. Due to the high LC ordering at the DPD temperature of T* = 0.40 k B T, a maximum LC ordering parameter is achieved, i.e., S u = 0.51 +/- 0.01. Consequently, significant polarization-dependent diffraction is observed, with a maximum diffraction efficiency of 92.5 +/- 0.3% and 69.3 +/- 5.4%, respectively, when probed by s- and p-polarized light. The cross-scale coupled DPD-FDTD simulation not only provides valuable insights into the fundamental structure-property relation of holographic polymer nanocomposites but also offers a viable tool to study structure-ordered materials.

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