Dr. Zhang Fusheng Advances Nanocellulose Research in ACS NANO

The research team successfully overcame the technical bottleneck of cellulose nanocrystals (CNC) in the preparation of chiral photonic filaments by using a continuous confined self-assembly mechanism, combined with shear-driven orientation, rapid photochemical cross-linking reaction and wet spinning technology (Figure 2). By optimizing processing parameters and applying heat treatment to strengthen hydrogen bonds within CNC molecules, the research team prepared photonic filaments with a length of more than 30 meters and a diameter of about 160 microns, while retaining the left-handed chiral nematic structure.

Figure 2 Flow chart of "confined self-assembly"

The photonic filaments exhibit excellent performance characteristics: a highly ordered hierarchical structure with an orientation order parameter of 0.91; excellent mechanical properties, stress up to 37 MPa, and toughness of about 14 MJ∙m−3; and excellent compatibility with water environments. Of particular note, these filaments exhibit significant interference color responses to moisture, viewing angle changes and mechanical stress, thanks to their high birefringence characteristics (∆n of 16.5 × 10−3) and significant optical path difference (> 2500 nm).

The research results have broad application prospects: photonic filaments can be processed by standard looms for textile processing, suitable for manual and machine weaving, and open up new avenues for smart textiles and fashion innovation (Figure 3). This technological breakthrough not only promotes the application of cellulose materials in photonic metamaterials, smart textiles and polarization soft fiber communications, but also provides innovative solutions for sustainable development.

Figure 3 Application potential display

The research was completed by Qing Guangyan, a researcher at the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, as the corresponding author, Wuhan Textile University as the first unit, and Dr. Zhang Fusheng, Master's graduate Yu Jiaqi and PhD student Zhong Wei of the University of Science and Technology of China as co-first authors. The relevant research results were published in "ACS NANO" under the title "Responsive Photonic Filaments from Confined Self-Assembly of Cellulose Nanocrystals".

Article link: https://doi.org/10.1021/acsnano.4c15863

In another study published in Materials Today, Dr. Zhang Fusheng collaborated with Researcher Qing Guangyan from the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, to successfully develop a photonic Bouligand structure hydrogel with dynamic mechanical color change properties. The study achieved a major breakthrough in material performance by redirecting the CNC chiral nematic structure (Figure 4) through crystal domain reduction and chain reconstruction technology.

Figure 4 Conceptual diagram of crystal torsion

The new photonic hydrogel exhibits excellent mechanical properties: stretchability exceeds 950% and toughness is as high as 155.5 MJ∙m−3. At the same time, the material exhibits a reversible color change with a wavelength shift of 427 nm and maintains a progressive electrical sensing response over a wide range of mechanical stretching. It is particularly worth mentioning that the research team successfully integrated the hydrogel into a microcontroller and constructed a mechanical imaging platform to achieve visual positioning of pressure distribution through optical and electronic dual signal reporting performance (Figure 5).

This innovative achievement marks a new era in the application of CNC materials, bringing innovative solutions to the medical, energy and industrial fields. This research not only opens up a new way to manufacture strong photonic hydrogels, but also provides important theoretical and technical support for the intelligent application of bionic photonic cellulose materials.