Structurally coloured organic–inorganic hybrid silica films with a chiral nematic structure prepared through a self-templating approach

Liu, Weiwei; Wei, Haohao; Li, Hongkun; Wang, Yong; Wu, Limin; Li, Baozong; Li, Yang; Yang, Yonggang

doi:10.1080/02678292.2020.1791984

Cited by 7 publications

(4 citation statements)

References 29 publications

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“…[28] The syntheses and characterizations of Bola-1 and CA-1 have been reported previously. [27] For the preparation of structural coloured OIHS film with a SmC* structure, mixtures of CSC, Bola-1 and CA-1 were prepared (Figure 1). Bola-1 shows a monotropic nematic phase (Cr 50.7 °C I 48.9 °C N 30.2 °C Recr).…”

Section: Resultsmentioning

confidence: 99%

“…It was calculated from previous results that the helical twisting power (HTP) value of CA-1 was about 100 μm À 1 . [27] Moreover, CA-1 could drive the formation of a right-handed helical supramolecular structure. Therefore, the cholesteric and SmC* phases of CSC are reasonable to exhibit right-handedness.…”

Section: Resultsmentioning

confidence: 99%

“…[26] Recently, we reported that the colourful OIHS films could be prepared through a self-templating approach. [27] The colour originated from the cholesteric structure. Therefore, structurally coloured OIHSs with other chiral LC structures become attractive.…”

Section: Introductionmentioning

confidence: 99%

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Anti‐counterfeiting Behaviour of Organic‐Inorganic Hybrid Silica Film with a Chiral Smectic C Structure

Sun

Chen

et al. 2022

Chemistry An Asian Journal

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Artificial photonic materials based on chiral liquid‐crystalline nanostructures have attracted increasing interests for their wide applications as sensors, anti‐counterfeit measures, displays and colour filters. Although the structurally coloured films with chiral nematic structures or blue phases have been prepared, the ones fabricated by fixing chiral smectic C (SmC*) phases have been rarely reported. In this work, organic‐inorganic hybrid silica (OIHS) films with a SmC* structure were reported for the first time. An organosilane (CSC) with an enantiotropic SmC* phase was synthesized. The OIHS films with a SmC* structure were fabricated by the polycondensation of CSC under an acidic condition. The colour patterns can be observed in the oblique view, but not be observed in the vertical view, which is mainly due to the light scattering of the nanoparticles on film surface and the selective Bragg reflection of film inside. Therefore, such properties make the OIHS films promising candidates for anti‐counterfeiting applications.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Anti‐counterfeiting Behaviour of Organic‐Inorganic Hybrid Silica Film with a Chiral Smectic C Structure

Sun

Chen

et al. 2022

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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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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Structurally coloured organic–inorganic hybrid silica films with a chiral nematic structure prepared through a self-templating approach

Cited by 7 publications

References 29 publications

Anti‐counterfeiting Behaviour of Organic‐Inorganic Hybrid Silica Film with a Chiral Smectic C Structure

Anti‐counterfeiting Behaviour of Organic‐Inorganic Hybrid Silica Film with a Chiral Smectic C Structure

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

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

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