High-Performance Polymer Dispersed Liquid Crystal Enabled by Uniquely Designed Acrylate Monomer

Abstract

The widespread electro–optical applications of polymer dispersed liquid crystals (PDLCs) are hampered by their high-driving voltage. Attempts to fabricate PDLC devices with low driving voltage sacrifice other desirable features of PDLCs. There is thus a clear need to develop a method to reduce the driving voltage without diminishing other revolutionary features of PDLCs. Herein, we report a low-voltage driven PDLC system achieved through an elegantly simple and uniquely designed acrylate monomer (A3DA) featuring a benzene moiety with a dodecyl terminal chain. The PDLC films were fabricated by the photopolymerization of mono- and di-functional acrylate monomers (19.2 wt%) mixed in a nematic liquid crystal E7 (80 wt%). The PDLC film with A3DA exhibited an abrupt decline of driving voltage by 75% (0.55 V/μm) with a high contrast ratio (16.82) while maintaining other electro–optical properties almost the same as the reference cell. The response time was adjusted to satisfactory by tuning the monomer concentration while maintaining the voltage significantly low (3 ms for a voltage of 0.98 V/μm). Confocal laser scanning microscopy confirmed the polyhedral foam texture morphology with an average mesh size of approximately 2.6 μm, which is less in comparison with the mesh size of reference PDLC (3.4 μm), yet the A3DA-PDLC showed low switching voltage. Thus, the promoted electro–optical properties are believed to be originated from the unique polymer networks formed by A3DA and its weak anchoring behavior on LCs. The present system with such a huge reduction in driving voltage and enhanced electro–optical performance opens up an excellent way for abundant perspective applications of PDLCs.

Recent Advances in The Polymer Dispersed Liquid Crystal Composite and Its Applications

“…Among them, the presence of the hydroxyl group promoted the formation of a thin polymer layer at the surface of PDLC films even at low LC loadings, attributed to improving the E-O properties [ 46 ]. Recently, a low-voltage driven PDLC system was achieved through an elegantly simple and uniquely designed acrylate monomer (A3DA) featuring a benzene moiety with a dodecyl terminal chain [ 47 ]. In our recent study, we focused on the comparison of methyl and acrylate monomers as well as terminal structures [ 48 ].…”

Effects of terpene alcohol dopant on the morphology and electro‐optical properties of polymer‐dispersed liquid‐crystal composite films

“…These parameters are affected by the physical properties of LC, the structures of monomers, and the morphology of the polymer network 13 . Generally, the strong anchoring effect of the polymer on the LC molecules leads to a high driving voltage, which limits the application of PDLC films 14 …”

“…13 Generally, the strong anchoring effect of the polymer on the LC molecules leads to a high driving voltage, which limits the application of PDLC films. 14 There are some available ways to reduce the driving voltage of the PDLC film. One is to adjust the composition ratio and the varieties of the monomers and LC, such as the chain length of the monomers and the structure of the LC monomer.…”

Design and Self-Assembling Behaviour of Calamitic Reactive Mesogens with Lateral Methyl and Methoxy Substituents and Vinyl Terminal Group

“…Utilisation of the various types of polymeric backbones (polyacrylate [ 16 ], polymethacrylate [ 4 , 21 , 22 , 24 ], polysiloxane [ 23 , 25 , 26 , 27 , 28 ], polyurethane [ 29 ], etc.) for the design of LC macromolecular materials requires a specific molecular structure of the reactive terminal groups (acrylate [ 16 , 30 , 31 , 32 , 33 ], methacrylate [ 4 , 21 , 22 , 32 ], vinyl [ 12 , 23 , 27 , 34 ], thiols [ 35 , 36 , 37 ], etc.) of the respective monomeric LC materials used as functional reactive mesogens.…”