Linking LC Architectures for Soft Mattonics

In 1991, in his Nobel acceptance speech, Pierre-Gilles de Gennes proposed “soft matter” for the first time. Soft matter includes materials between aqueous substances and ideal solids.

Soft matter materials with a broad range of multifaceted configurations, metastable states, colorful patterns, and macroscopic softness have offered beneficial inspirations for resolving contemporary challenges in photonics and optics.

Self-assembled LC signifies one of the most striking soft matter platforms. Its microstructures display the advantages of smooth fabrication, high flexibility, excellent tunability, and extraordinary stimuli-responsiveness.

Over the last few years, optical platforms based on LCs have rapidly developed, stimulating the growth of novel phenomena, applications, and functions.

It is of growing significance to discuss the latest progress of LC-architectures-based soft matter photonics (Soft Mattonics) from an all-inclusive viewpoint to offer a valuable reference for the future advance of the related realm.

A group of researchers, headed by Professor Yan-Qing Lu from the National Laboratory of Solid State Microstructures, Key Laboratory of Intelligent Optical Sensing and Manipulation, and College of Engineering and Applied Sciences, Nanjing University, China, and co-workers have performed a systematic and detailed review to bridge different dynamically adjustable LC architectures with their various applications in Soft Mattonics.

Details of their research can be found in the journal Light Sciences and Applications.

This article comprehensively defines the standard definitions, manipulation schemes, physical properties, and dynamic controllability of usual thermotropic LCs and bio-based lyotropic LCs, including smectic phase LCs, nematic phase LCs, blue phase LCs, cholesteric phase LCs, and celluloses.

The representative textures, schematic configurations, and potential applications of these liquid crystalline materials are illustrated in the image above.

Microstructures link the innate features of nanomaterial to significant functionalities, playing a major role in creating suitable LC-based optics and photonics. At one end of the spectrum, regulating LC microstructures is the creation.

It can be reached by merging the “top-down” manufacturing method with the “bottom-up” self-assembly procedure of LCs.

For instance, substrates with three-dimensional (3D) topographic surface patterning can be used to produce ordered topological defect arrays, as the 2D photoaligned layer activates a flexible construction of 3D LC superstructures.

At the other end of the spectrum is the detailed tunability of LC architectures. Many efforts have been devoted to this field to dynamically exploit the LC structures by incorporating light, heat, stress, electricity, and magnetic field, sometimes combined.

With the exhibited work, Lu and co-workers offered an introduction to LC-based devices in the swiftly growing domain of Soft Mattonics, such as smart displays, light field modulation devices, smart windows, optical imaging, and soft actuators. It brings striking, efficient, tunable, and numerous functionalities/performances to the soft-matter-based optical systems.

The researchers also emphasized the opportunities and challenges these materials present for soft matter photonics:

1. Mass production and processing
2. Merging LCs with other soft materials
3. Realizing enhanced “structure-property-function” relationships
4. Incorporating LCs with innovative robotic and electronic systems
5. Seamless incorporation of soft matter materials with current optical parts
6. Recently discovered LC phases

Additional exploration in a rapidly expanding subject would not only widen the knowledge of Soft Mattonics but also boost multidisciplinary exploration from experts across various disciplines and encourage diverse, smart, and soft photonic applications.

Journal Reference

Ma, L-L., et al. (2022) Self-assembled liquid crystal architectures for soft matter photonics. Light Sciences and Applications. doi.org/10.1038/s41377-022-00930-5.