Poly (p-phenylene terephtalamide)(PPTA) is a kind of lyotropic liquid crystal polymer. Fiber material consisted of oriented PPTA molecules has excellent mechanical strength and is necessary in many important areas. However, the poor processability of PPTA due to its non-melting and insoluble characteristics seriously limits the expansion of PPTA application. Self-assembly of PPTA into nanofibers and further processing the nanofibers into macroscopic materials is an effective strategy to solve the problem of PPTA processing. This paper briefly reviews the self-assembly methods of PPTA in recent years, and mainly introduced the fabrication of different kinds of macroscopic materials from monomers through the combination of in-situ self-assembly and other self-assembly methods. This multi-level self-assembly strategy realizes the processing of liquid crystal polymer PPTA, enrich the product variety, and is expected to be applied to the self-assembly of other liquid crystal polymers.

Thermotropic liquid crystalline polyarylate(TLCP) is an essential type of thermotropic liquid crystal polymers which exhibit excellent mechanical properties, good thermal stability, stable dielectric properties and flexibility in processing. With the advent of information age and ever-growing demand for green chemistry, TLCP will occupy an increasingly broad market. From the perspective of polymer synthesis, structure and performances, engineering applications, this review summarizes the recent research progress of TLCP. To begin, the TLCP synthesis methods are described. From the standpoint of molecular design, the primary optimization solutions are described in detail in relation to the disadvantages of TLCP during processing, such as high melt temperature and high melt viscosity. Second, some commercialized TLCPs are introduced, further both the film and fiber variants of TLCP processing are covered. Finally, the main application areas of TLCP are briefly discussed.

Polysiloxane side-chain liquid crystalline polymers(PSLCPs)are a class of liquid crystal polymer that branches liquid crystal monomer or special functional group to the siloxane main chain through a crosslinking reaction. Due to the soft and flexibility of the siloxane main chain and the photo-/thermo-/electric response characteristics of functional groups, polysiloxane side-chain liquid crystalline polymers are widely used in optical information storage, nonlinear optics, image display, chromatography, current change, etc. In this paper, the research progress made by polysiloxane side-chain liquid crystalline polymers in the fields of wide-band reflection, flexible photo response devices, flexible optical paints and stress/electrical response devices are reviewed and discussed, and the future development trends is forecasted.

The “Mesogen-Jacketed” liquid crystal polymers (MJLCPs) simultaneously show the structures of side-chain liquid crystal polymers and the properties of main-chain liquid crystal polymer, which exhibit different ordered structure, excellent structure ability and physical property. The performances make them widely application in functional materials. This work summarizes the latest developments in the design and synthesis of MJLCPs as functional materials in recent years as well as the relationship between structures and performances, including high-temperature thermoplastic elastomers, polymer electrolytes, photoluminescent liquid crystal, polymer electroluminescence, and polymer solar cells, and the prospect of their further development is also given.

Photo-responsive liquid-crystalline polymers (LCPs) containing photoisomerizable molecular switches (such as azobenzene, AZ) or photothermal agents (such as graphene), are a type of widely investigated smart materials, which can undergo an order-disorder transition, inducing a macroscopic shape change. Presently, light-driven oscillators of LCPs have been achieved mainly by two methods. One is that the actuator displays chaotic swing for the nonlinear change of mechanical properties of LCPs containing AZs under continuous UV or visible light illumination. The other is constructing nonequilibrium systems and relying on the self-shadowing effect during motion. The actuator can realize periodical and sustained motion without additional manual control components, which can be extensively exploited in light signal modulation, mobile robots, energy harvesting, mills, motors, etc. This paper reviews the research progress of light-driven oscillators of LCPs in the past few years, and also introduces its fabrication methods, motion mechanisms and application areas in details. Finally, it provides a view of prospective of its future development trend for light-driven oscillators of LCPs.

Liquid-crystalline elastomers (LCEs) are a type of smart materials that can produce macroscopic reversible deformation under external stimuli (such as heat, light, electricity, magnetism, etc.). Only LCEs that are aligned can exhibit macroscopic reversible deformation. Dynamic covalent bonds can be reversibly broken and regenerated under certain conditions, which can change the topological structure of traditional covalent cross-linked networks. Introducing dynamic covalent bonds into LCEs enables a new strategy to align the material. Liquid-crystalline elastomer reversible three-dimensional structures have certain three-dimensional shapes and can produce reversible deformation under external stimuli, which can be used in biomedicine, tissue engineering, aerospace, and flexible robots. In order to obtain liquid-crystalline elastomer reversible three-dimensional structures with more complex shapes and multiple deformation modes, the liquid-crystalline elastomers can be three-dimensionally aligned or assembled based on the orientation method of dynamic covalent bonds. This article reviews the processing methods of the liquid-crystalline elastomer reversible three-dimensional structures based on dynamic covalent bonds, and analyzes the challenges and opportunities in this field.

Actuator has aroused enormous research avocation due to its excellent performance and promising applications in the field of soft robots, artificial muscles, etc. By introducing azobenzene mesogens into the actuation material, a non-contact, precise control, and low energy consumption photo-responsive actuator can be realized based on the reversible photoisomerization process of azobenzene mesogens. After years of development, the materials of azobenzene liquid crystal actuator have gone through the initial polysiloxanes, polyacrylates, etc., to advanced dynamic transesterification networks. The development of actuation materials has further promoted the diversification and functionalization of actuation forms. The actuation form of the azobenzene liquid crystal actuator ranges from simple bending, twisting, and oscillating to more practical light-controlled motors, lifting heavy objects, micro liquid transportation and etc. This paper summarizes and reviews the development history, typical applications, and current problems of the azobenzene liquid crystal actuator. Finally, its application prospect in the field of energy conversion is prospected.

In recent years, carbon nanotube/liquid crystal elastomer (CNT-LCE) composite materials have received lots of scientific attention in the field of stimuli-responsive LCEs, due to the stable and efficient photothermal conversion properties. However, most researchers focused their attention on the stimuli-responsive behavior and application scenarios, but ignored the investigation of the effect of CNTs influencing on the mechanical properties of the LCE materials. Herein, a series of CNTs incorporated LCE composite films are prepared, and further characterized and analyzed by Fourier infrared spectroscopy, differential scanning calorimeter, wide-angle X-ray diffractometer and dynamic thermo-mechanical analyzer to explore the thermal, mesomorphic and mechanical properties of the composite films. The experimental results show that the doping amount of CNTs markedly influences the mechanical properties of these prepared CNT-LCE composite materials. Among them, the 8% (Mass fraction) CNTs incorporated LCE composite film exhibits the best mechanical properties. At 30 ℃, the breaking strength of the composite film is 5.62 MPa, and the breaking elongation is 182%. Beyond the clear point temperature, the breaking strength of the composite film is 1.62 MPa, and the elongation at break is 89%. Particularly, the breaking strength of this 8% CNTs incorporated LCE film is almost three times that of the pure LCE film. Besides, the CNT-LCE composite film can achieve a reversible shrinking deformation with a maximum contraction rate of 45%, which endows this material with a good application prospect in the field of intelligent materials, such as artificial muscle and soft robots, etc.

The problem of energy depletion has become an obstacle to the sustainable development of human society. According to statistics, Chinese building energy consumption accounts for 20% of our total energy consumption. Therefore, it is of paramount importance to intelligently manage the solar radiation and infrared thermal radiation of objects, achieving the self-adaption of environmental temperature while reducing energy consumption. This work summarizes the state-of-the-art advancements of bioinspired intelligent polymer materials for optical and thermal management, which includes temperature-adaptive polymer materials with dynamic modulation of solar radiation and infrared thermal radiation. The temperature-adaptive polymer materials including liquid crystals and hydrogels for dynamic modulation of solar radiation are introduced firstly, then the advanced polymer materials with tunable emissivity in the mid-wavelength and long-wavelength infrared spectral range are illustrated for dynamic modulation of infrared thermal radiation. This review concludes with a perspective on the opportunities and challenges for the future development and potential applications of emerging bioinspired intelligent polymer materials for optical and thermal management.

The blue phase is a highly chiral liquid crystal phase state that is usually between the isotropic state and the cholesteric phase. Because of its unique optical isotropy, fast electric field response and selective reflection wavelength and other optical properties, the blue phase liquid crystals have good development prospects in liquid crystal displays, optical devices, and tunable three-dimensional photonic crystals. Therefore, in recent years, blue-phase liquid crystal materials have attracted a lot of attention from researchers at home and abroad. This article reviews the development process of blue-phase liquid crystals, the research progress of blue-phase liquid crystal network polymers, and the current status of their applications in innovative applications. The application limitations of blue-phase materials in the fields of display and microelectronics are discussed, and the opportunities and challenges of blue-phase liquid crystal and blue-phase network polymers in the design of advanced functional materials and device applications are summarized.