Transparent UV-blocking photonic film based on reflection of cholesteric liquid crystals

A hyper-reflective cholesteric liquid crystal polymer network with double layers

“…37 To increase the reflectance, double-layered CLCN films constructed using left-and righthanded CLCN films were also prepared. [38][39][40] The reflectance of the film can reach 98%. Moreover, the hyper-reflective CLCN films can also be prepared using a half wave retarder.…”

Polymer Network Film with Double Reflection Bands Prepared Using a Thermochromic Cholesteric Liquid Crystal Mixture

“…The helical pitch ( P ) of CLCs is generally uniform. , Based on the Bragg equation, the reflection wavelength at the maximum (λ) is given by λ = n × P ( n , the average refractive index), and the reflection bandwidth Δλ is given by Δλ = Δ n × P . Generally, the Δ n values of liquid crystals are around 0.1–0.2 , and the bandwidth of the CLCs is narrow, which is hard to meet some application requirements, such as reflective displays, color decoration, , and anticounterfeiting. − In previous reports, in order to obtain optical filters with double reflection bands, the stacking of CLC polymer network (CLCN) layers with different pitches seems to be a simple option. − Due to the dislocation of the molecular packing at the laminated interface, light scattering was caused. Through the refill methods, CLCN and polymer-stabilized CLC films with double reflection bands were also prepared. − It was reported that CLCN films with double reflection bands could be prepared using photochromic CLC mixtures .…”

Polymer-Stabilized Cholesteric Liquid Crystal Films with Double Reflection Bands Prepared Based on the Competition between Photopolymerization and Photoisomerization

“…Reactive CLC mixtures were generally prepared using nematic liquid crystals (LCs) and chiral dopants. To fix the structural color, several kinds of polymer-stabilized CLC (PSCLC) films were prepared, including polyacrylates, − epoxy , and oxetane resins, , polysiloxanes , and organic–inorganic hybrid silicas. − The structural color was controlled by changing the concentration of the chiral dopant or the polymerization condition. These films can be used in optics, , sensors, − displays, decoration , and anti-counterfeiting. , For the preparation of PSCLC films with double reflection bands, several methods have been developed.…”

“…These films can be used in optics, , sensors, − displays, decoration , and anti-counterfeiting. , For the preparation of PSCLC films with double reflection bands, several methods have been developed. They can be simply prepared by stacking two PSCLC films with different reflection bands. − This method of multilayer system is also used to broaden the reflectance bandwidth. , They have also been prepared through refill methods. − Based on these methods, the PSCLC films with hyper-reflectance have also been prepared . They can also be prepared using thermochromic and photochromic CLC mixtures. − …”