Fluoride anion (F–) recognition has attracted much attention in recent years due to its significant role in biological, medical, environmental, and industrial processes. Although many artificial receptors show high sensitivity toward F–, they still lack the specificity for such an anion. It still remains a great challenge to endow the receptors with high specificity and sensitivity toward F– at the same time. Herein, a contracted cis-cisoid poly­(phenylacetylene) derivative (Poly-1) has been synthesized, whose preferred-handed helix can be stabilized by intramolecular hydrogen bonding networks among neighboring pendant amides. The average layer distance between its side chains of 3.88 Å can provide a small pocket, which is suitable to accommodate the smallest anion F– with high basicity, but excludes other anions. When the first F– binds to the pendant amides via intermolecular hydrogen bonding, the main chain conformational transition into a stretched cis-transoid nonpreferred-handed helix is triggered, which facilitates the subsequent F– binding. Such an unzipping effect gives rise to an ultralow detection limit of 2.85 × 10–8 M (0.54 ppb) for F–. Meanwhile, the solution color change from colorless to yellow can be observed because of the conjugated cis-transoid conformation of Poly-1. As a result, a highly specific and sensitive naked-eye recognition toward F– is realized. This work lays a solid foundation for the development of smart materials on the basis of stimuli-responsive cascade processes.

The yarn weave architectures highly influence the mechanical response of woven fabrics. To provide an accurate prediction of the mechanical behaviors of woven fabrics under tension, a mesoscale model is developed. The model takes into account yarn properties, yarn weaving pattern, and interactions between yarns. The yarn properties such as tensile modulus and yarn strength of yarns are considered as random variables. Each yarn in fabric is modeled as a Timoshenko beam with a weaving shape modeled by a parabolic function. The yarn shape evolution and mechanical response of undulated yarn under tension are computed based on Castigliano’s second theorem. The damage initiation and propagation of a yarn in fabric is introduced through a damage variable. The model is demonstrated on woven jute fabrics. Analytical and numerical analyses are carried out and show good prediction on the macroscopic tensile response of woven jute fabric. The model provides a quantitative understanding between yarn geometrical parameters and the expected material response, and makes it helpful for designing woven structural composites with high performance.

No abstract

No abstract

Modern material design aims to achieve multifunctionality through integrating structures in a diverse range, resulting in simple materials with embedded functions. Biological materials and organisms are typical examples of this concept, where complex functionalities are achieved through a limited material base. This review highlights the multiscale structural and functional integration of representative natural organisms and materials, as well as biomimetic examples. The impact, wear, and crush resistance properties exhibited by mantis shrimp and ironclad beetle during predation or resistance offer valuable inspiration for the development of structural materials in the aerospace field. Investigating cyanobacteria that thrive in extreme environments can contribute to developing living materials that can serve in places like Mars. The exploration of shape memory and the self-repairing properties of spider silk and mussels, as well as the investigation of sensing–actuating and sensing–camouflage mechanisms in Banksias, chameleons, and moths, holds significant potential for the optimization of soft robot designs. Furthermore, a deeper understanding of mussel and gecko adhesion mechanisms can have a profound impact on medical fields, including tissue engineering and drug delivery. In conclusion, the integration of structure and function is crucial for driving innovations and breakthroughs in modern engineering materials and their applications. The gaps between current biomimetic designs and natural organisms are also discussed.