Photonic hydrogel of high solid cellulose with reconfigurability

Recently, Qing Guangyan, a researcher team from the Research Group on Bioseparation and Interface Molecular Mechanism (1824 Group) of Biotechnology Research Department of Dalian Institute of Chemical Physics, Chinese Academy of Sciences, designed and prepared a highly solid cellulose photonic hydrogel with reconfigurability and mechanical discoloration. This preparation method opens up a new way to manufacture solid photonic hydrogels, and its intelligent optical response characteristics are expected to expand the application of bionic photonic cellulose materials in medical, energy and industrial fields.

The structure of Bouligand, which mimics the natural world, exhibits excellent mechanical properties due to its interlayer coupling and stress transfer mechanism, inspiring the development of high-performance materials such as impact resistant bioplastics, ceramic protective clothing, and biomimetic alloy composites. Although significant progress has been made in engineering plasticity through molecular level design and multi-scale structural optimization of biomimetic Bouligand structures, most existing materials are composed of single scale brittle units, lacking graded active interfaces and autonomous response capabilities, resulting in limited ductility and functionality. Therefore, it is necessary to break through the existing design bottlenecks and develop a new Bouligand structural material system that simultaneously possesses multi-level active interfaces, dynamic response capabilities, and high toughness, in order to enhance and optimize the rigidity and ductility of the material. Building strategies that balance micro motion and structural robustness, fundamentally breaking the contradiction between brittleness and toughness, and overcoming key technical challenges that hinder the practical application of biomimetic materials, is expected to solve the above-mentioned problems.

In this work, the team provided a widely applicable solution for the Bouligand structure through self-assembly of cellulose nanocrystals (CNC). This strategy achieves precise control of the spatial arrangement of the network matrix through nanofiber sliding and hydrogen bonding reconstruction. This transition is driven by the hydrogen bond action activated by water molecules to form a solid photonic hydrogel. The obtained Bouligand structure hydrogel shows excellent mechanical properties. Compared with the initial hydrogel, its toughness value has increased by 5 times, reaching 155.5MJ/m&# 179;, Stretchability exceeds 950%. In addition, these photonic hydrogels exhibit dynamic color change ability, can switch between red and blue, and maintain stable electrical sensitivity during reversible stretching. The imaging interface of the photonic hydrogel is durable and can be used repeatedly. It only needs to soak in water for 5 minutes to restore its activity. This work has opened up a new path for the practical application of CNC, which is expected to be applied in fields such as sustainable bioplastics, flexible electronic substrates, and intelligent photonic devices.

In recent years, the team led by Qing Guangyan has made a series of progress in the chiral functionalization research of nanocellulose. In the early stage, they have developed multi-mode and convertible chiral optical anti-counterfeiting films (Adv. Funct. Mater., 2022), flexible sweat sensors based on photonic cellulose nanocrystals (Small, 2023), left-handed circularly polarized luminescent cellulose films (Adv. Mater., 2024), and synergistic color changing and conductive cellulose nanocrystal photonic patches (Mater. Horizon., 2024).

The related research findings, titled "Highly robust cellulose photonic hydrogels with reconfigurability and mechanochromism," were recently published in Materials Today. The first author of this work is Li Qiongya, a doctoral student from the 1824 group of the institute.

Source: opticsky