Colorful patterned organic–inorganic hybrid silica films with a cholesteric structure

Xu, Tao; Yu, Runwei; Liu, Wei; Li, Hongkun; Li, Yang; Yang, Yonggang

doi:10.1007/s10971-022-05926-6

Cited by 6 publications

(4 citation statements)

References 38 publications

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“…[4,6] Recently, several colourful PSCLC patterns were prepared using the photochromic CLC mixtures with the addition of a photoisomerizable chiral additive. [9,19] The structural colour was tuned by changing the helical pitch. Herein, a photochromic CLC mixture was prepared using a mixture of two chiral additives, the handedness of which was able to be changed by UV light irradiation.…”

Section: Introductionmentioning

confidence: 99%

“…For anti‐counterfeiting, the colourful patterns were prepared using the structurally coloured materials including the PSCLC [4,6] . Recently, several colourful PSCLC patterns were prepared using the photochromic CLC mixtures with the addition of a photoisomerizable chiral additive [9,19] . The structural colour was tuned by changing the helical pitch.…”

Section: Introductionmentioning

confidence: 99%

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A PSCLC Pattern Prepared Based on Handedness Inversion for Anti‐counterfeiting

Zhao,

Yu,

et al. 2023

Chemistry An Asian Journal

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Handedness inversion has been widely studied in supramolecular chemistry and material sciences. Herein, a photoisomerizable chiral dopant was synthesized, which could induce the formation of a cholesteric phase with right‐handedness. The Bragg reflection band of the cholesteric liquid crystal (CLC) mixture shifted to the long wavelength with extending 365 nm UV light irradiation time. Based on this photochromic property, a colourful polymer‐stabilized CLC (PSCLC) film was prepared using a grayscale mask. A handedness reversible CLC mixture was prepared using a mixture of this chiral dopant and S5011. With extending the UV light irradiation time, the handedness of the CLC mixture changed from right‐ to left‐handedness. A patterned PSCLC film was prepared using this CLC mixture. Complementary images were observed under right‐ and left‐handedness circularly polarized lights. The results shown here not only give us a better understanding the competition between photopolymerization and photoisomerization, but also lay the foundations for decoration and anti‐counterfeiting.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A PSCLC Pattern Prepared Based on Handedness Inversion for Anti‐counterfeiting

Zhao,

Yu,

et al. 2023

Chemistry An Asian Journal

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“…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.…”

Section: Introductionmentioning

confidence: 99%

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

Wang,

Zhao,

et al. 2023

ACS Appl. Mater. Interfaces

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Composite colors have been widely found in nature. Herein, polymer-stabilized cholesteric liquid crystal (PSCLC) films with composite structural colors were prepared through a one-step photopolymerization approach. The CLC mixtures were prepared using a mixture of acrylates and a mixture of two chiral dopants. One of the chiral dopants is polymerizable, and the other one is photoisomerizable. After photopolymerization, the PSCLC films with double Bragg reflection bands were obtained on the surface of a substrate. The competition between the photopolymerization of the acrylates and the photoisomerization of the chiral dopant was proposed to drive the formation of the double reflection bands. Without oxygen inhibition, the polymerization of the acrylates near the substrate surface was carried out. However, due to oxygen inhibition, the polymerization of the acrylates near the air was retarded. Then, the photoisomerization of the chiral dopant was carried out prior to the polymerization of the acrylates. The wavelengths of the double reflection bands were tunable by changing the concentrations of the acrylates and chiral dopants and the polymerization temperature. Colorful patterns with composite structural colors were prepared, which were suitable for decoration and anticounterfeiting.

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“…[24][25][26] To solve that problem, photoisomerizable materials like azobenzene were added to realize the "light" programming of nanostructure by changing light exposure conditions. [28][29][30][31] In addition, based on the irreversible mechanical response, imprinting technology was also used to program the refractive index of the nanostructure. [32,33] In pursuit of higher-level encryption, steganography, realized by writing patterns and information in the stimulated state through programming response characteristics, is widely used in multicolor anticounterfeiting.…”

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confidence: 99%

Hybrid Encoding Strategy of Nanostructures for High‐Performance Security Information Encryption

Zhu

et al. 2023

Advanced Optical Materials

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specific external stimuli [14][15][16][17] can be used to carry and transmit unique information, so that SPCs have wide potential applications in fields of displays, lasing, and information security. [18][19][20] Cholesteric liquid crystal polymers/ films (CLCPs/CLCFs) are self-assembled 1D SPCs. [21][22][23] Bright structural color is produced by their unique helical nanostructures. The Bragg center wavelength (λ B ) of CLCPs/CLCFs depends on the pitch (p) of their helical nanostructure and the average refractive index of liquid crystal mixture () determines the Bragg center wavelength (λ B ) of CLCPs/CLCFs. The encrypted information can be written by programming colors with different strategies and recoded by ultraviolet (UV) irradiation. The p of CLCPs/CLCFs consisting of reactive small molecule mono mer or oligomer can be easily changed by external stimuli, including temperature [24,25] and electric field. [26,27] However, the change of λ B is usually retained by the polymerization of acrylate monomers. [24][25][26] To solve that problem, photoisomerizable materials like azobenzene were added to realize the "light" programming of nanostructure by changing light exposure conditions. [28][29][30][31] In addition, based on the irreversible mechanical response, imprinting technology was also used to program the refractive index of the nanostructure. [32,33] In pursuit of higher-level encryption, steganography, realized by writing patterns and information in the stimulated state through programming response characteristics, is widely used in multicolor anticounterfeiting. For example, the polymer containing hydrogen bonds was treated with the alkaline K + /Ca 2+ solution to obtain a humidity response, which could be programmed by the solution concentration. [34][35] It is a more common strategy to program the different response characteristics of polymers through different exposure conditions (time [36] and intensity [25,37] ). The nanostructure and mechanical response characteristics of CLCPs were programmed by the Michael addition reaction (MAR) time. [38] Combined with mask exposure technology, high-encrypted structural color pattern steganography was achieved. The single programming of nanostructure and response characteristics (structural color in the stimulated state) was discussed in detail in these works. Recently, our group presented a complex biomimetic structure with programmable synergistic shape transformations and nanostructure changes Programing nanostructure of soft photonic crystal materials to try to diversify has great potential for application in the field of information security, lasing, and display. However, complex programming nanostructures for regulating and controlling their structural color and stimuli-response behavior remain a technical challenge. Here, a strategy is demonstrated for hybrid encoding nanostructures of soft photonic crystals using cholesteric liquid crystal films (CLCFs). The public and secure information can be easily edited through the independent tuning of Bragg ce...

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Colorful patterned organic–inorganic hybrid silica films with a cholesteric structure

Cited by 6 publications

References 38 publications

A PSCLC Pattern Prepared Based on Handedness Inversion for Anti‐counterfeiting

A PSCLC Pattern Prepared Based on Handedness Inversion for Anti‐counterfeiting

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

Hybrid Encoding Strategy of Nanostructures for High‐Performance Security Information Encryption

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