Scalable Photonic Liquid Crystal Nanoscale-Thick Films for Deformation and Discoloration

Abstract

A self-assembled three-dimensional (3D) nanomaterial, blue phase liquid crystal (BPLC), with elastic deformation is the aim of a stimuli-responsive material because it combines the 3D photonic nanostructure and the rubber elasticity of the elastomer network. However, there is still a lack of a flexible approach to preparing BPLC films with high elastic deformation and a low glass-transition temperature. Here, we develop a reproducible and scalable two-step protocol of the thiol-acrylate Michael addition (TAMA)–photopolymerization reaction approach for the preparation of high-performance, low glass-transition temperature, and uniform BPLC films. Linear chain extension occurs through the TAMA reaction, and the cross-link density and molecular weight can be programed by varying the reaction time, resulting in the phase transition from blue phase I to the chiral nematic phase. The cross-linking density, molecular weight, and resulting structure can be frozen by forming an elastic network using photopolymerization. The results show that the increase of elastic deformation by 3 times, shift of the structural color >186 nm, and lowering of the glass-transition temperature to −34.93 °C are successfully achieved. In addition, the BPLC film pattern can sustain repeatable, rapid, and continuous elastic deformation and a uniform structural color change when triggered by multiple stimuli of temperature, stretching, and organic vapor. This work provides new insights into customizable stimuli-responsive 3D photonic nanostructured materials, facilitating their application in sensing, display, and anti-counterfeiting.

Smart chiral liquid crystal elastomers: Design, properties and application

“…Recently, adopting the most popular protocol for LCE synthesis, that is, the thiol-acrylate Michael addition reaction and photopolymerization, Zhu and coworkers developed homogeneous and high-performance BPLCE films with low glass-transition temperature (−34.93°C), high stretchability (310% strain), and long wavelength shift (>186) from red (628 nm) to green and then to blue (442 nm). [114] This research provides new insights into adaptable 3D photonic nanostructured materials that are stimuli-responsive facilitating their use for sensing, displays, and counterfeit detection. A major advantage of preparing functional materials from BPs is the ability to form single crystals over a large area and thickness.…”

“…In either case, whether the strain is symmetric (by heat or swelling) or asymmetric (by mechanical force), the deformation is always reversible, which would further extend the application scope of BPLCEs to nonlinear optics, lasers, spectral imaging, and sensing. Recently, adopting the most popular protocol for LCE synthesis, that is, the thiol‐acrylate Michael addition reaction and photopolymerization, Zhu and coworkers developed homogeneous and high‐performance BPLCE films with low glass‐transition temperature (−34.93°C), high stretchability (310% strain), and long wavelength shift (>186) from red (628 nm) to green and then to blue (442 nm) [114] . This research provides new insights into adaptable 3D photonic nanostructured materials that are stimuli‐responsive facilitating their use for sensing, displays, and counterfeit detection.…”

A blue phase liquid crystal film based on an interpenetrating network and its sensitive humidity response performance

“…[20][21][22][23][24] Many researchers have explored the BPLC stimulus response. 13,[25][26][27][28][29][30] Hu et al designed a large number of hydrogen bond units and a high proportion of polymerizable monomers to construct a selfassembled three-dimensional nanostructure of BPLCSs and generate independent BPLCSs with humidity-responsive behavior. 31 Yang et al designed a moisture-driven chromogenic photonic polymer coating of a hydrogen-bonded 3D blue-phase liquid crystal network which could achieve a moisture-driven reversible color change in the visible spectrum upon breaking the hydrogen bond and subsequent conversion to a hygrophilic polymer coating.…”

Large Thermally Irreversible Photoinduced Shift of Selective Light Reflection in Hydrazone‐Containing Cholesteric Polymer Systems

“…Liquid crystals (LCs) are typical representatives of soft matter and demonstrate various types of mesomorphic structures that are easily controlled using external fields, such as electric fields, [1] magnetic fields, [2] mechanical actions, [3][4][5][6] and light exposure -for the systems containing photochromes. [7,8] If the photochromic groups have an anisometric shape, then they can also act as mesogenic fragments responsible for the mesophase formation.…”