Light Intensity-Selective Photopolymerization and Photoisomerization for Creating Colorful Polymer-Stabilized Cholesteric Liquid Crystal Patterns

Yu, Runwei; Cao, Yu; Chen, Kai; Li, Yi; Liu, Wei; Li, Baozong; Li, Hongkun; Yang, Yonggang

doi:10.1021/acsami.2c10763

Cited by 26 publications

(17 citation statements)

References 62 publications

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“…The diacrylate LC242 exhibits a nematic phase between 70 and 120 1C, which has been used for the preparation of the CLCN films. 45,47 Chiral dopant CA-iso is reactive, which can be fixed within the polyacrylate network. Moreover, it can drive the formation of the right-handed helical cholesteric structure.…”

Section: Resultsmentioning

confidence: 99%

“…43 The photoinitiator 907 can effectively suppress oxygen inhibition. 45 Therefore, the photopolymerization of acrylates can be carried out in air. The POM images of the LC242/CA-iso/907 (w/w/w, 92.17/ 4.83/3) and LC242/S5011/907 (w/w/w, 94.5/2.5/3) mixtures were taken at 80 1C during the cooling process.…”

Section: Resultsmentioning

confidence: 99%

“…Since this polymerization can be carried out in air, it is feasible for these films to be prepared with a large area. 45 The UV-vis spectra of the films are shown in Fig. 2.…”

Section: Resultsmentioning

confidence: 99%

“…38,43 Since the oxygen inhibition could be suppressed with the addition of a photoinitiator with a tertiary amino group, 44 the large-area CLCN films could be prepared on a coating line, which were potentially applied for decoration and anticounterfeiting. 45,46 Herein, the double-layered CLCN films constructed by the left-and right-handed helical CLCN films were prepared. Their reflectances were higher than 90%.…”

Section: Introductionmentioning

confidence: 99%

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

Zhang,

Zhao,

Yao

et al. 2023

New J. Chem.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

“…Since this polymerization can be carried out in air, it is feasible for these films to be prepared with a large area. 45 The UV-vis spectra of the films are shown in Fig. 2.…”

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Zhang,

Zhao,

Yao

et al. 2023

New J. Chem.

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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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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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Light Intensity-Selective Photopolymerization and Photoisomerization for Creating Colorful Polymer-Stabilized Cholesteric Liquid Crystal Patterns

Cited by 26 publications

References 62 publications

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

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

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

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

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