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A new bio-inspired algorithm, namely Bird Swarm Algorithm (BSA), is proposed for solving optimisation applications. BSA is based on the swarm intelligence extracted from the social behaviours and social interactions in bird swarms. Birds mainly have three kinds of behaviours: foraging behaviour, vigilance behaviour and flight behaviour. Birds may forage for food and escape from the predators by the social interactions to obtain a high chance of survival. By modelling these social behaviours, social interactions and the related swarm intelligence, four search strategies associated with five simplified rules are formulated in BSA. Simulations and comparisons based on eighteen benchmark problems demonstrate the effectiveness, superiority and stability of BSA. Some proposals for future research about BSA are also discussed.

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Through structure design, 3D printing enables the fabrication of mechanically durable superhydrophobic membranes with an ordered porous structure for oil–water separation.

Materials possessing exceptional temperature sensitivity and high stretchability are of importance for real-time temperature monitoring on threedimensional components with complex geometries, when operating under various external deformation modes. Herein, we develop a stretchable temperature sensor consisting of cellular graphene/polydimethylsiloxane composite. The first of its kind, graphene-based polymer composites with desired microstructures are produced through a direct 3D ink-writing technique. The resultant composites possess longrange-ordered and precisely controlled cellular structure. Temperature-sensing properties of three cellular structures, including grid, triangular, and hexagonal porous structures are studied. It is found that all three cellular composites present more stable sensitivities than solid composites under external strains because of the fine porous structure that can effectively share the external strain, and the composites with a grid structure delivered particularly a stable sensing performance, showing only ∼15% sensitivity decrease at a large tensile strain of 20%. Taking full advantage of the composites with a grid structure in terms of sensitivity, durability, and stability, practical applications of the composite are demonstrated to monitor the cooling process of a heated tube and measure skin temperature accompanying an arbitrary wristwork.

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Two star-like trimeric cationic surfactants with amide groups in spacers, tri(dodecyldimethylammonioacetoxy)diethyltriamine trichloride (DTAD) and tri(dodecyldimethylammonioacetoxy)tris(2-aminoethyl)amine trichloride (DDAD), have been synthesized, and the aggregation behavior of the surfactants in aqueous solution has been investigated by surface tension, electrical conductivity, isothermal titration microcalorimetry, dynamic light scattering, cryogenic transmission electron microscopy, and NMR techniques. Typically, both the surfactants form vesicles just above critical aggregation concentration (CAC), and then the vesicles transfer to micelles gradually with an increase of the surfactant concentration. It is approved that the conformation of the surfactant molecules changes in this transition process. Just above the CAC, the hydrophobic chains of the surfactant molecules pack more loosely because of the rigid spacer and intramolecular electrostatic repulsion in the three-charged headgroup. With the increase of the surfactant concentration, hydrophobic interaction becomes strong enough to pack the hydrophobic tails tightly and turn the molecular conformation into a pyramid-like shape, thus leading to the vesicle to micelle transition.

Covalent-organic frameworks (COFs) as porous crystalline materials show promising potential applications. However,d eveloping facile strategies for the construction of COFs directly from amorphous covalent organic polymers (COPs) is still agreat challenge.T othis end, we report anovel approach for easy preparation of COFs from amorphous COPs through the linkage replacement under different types of reactions.F our COFs with high crystallinity and porosity were constructed via the linkage substitution of polyimide-linked COPs to imine-linked COFs as well as imine-linked COPs to polyimide-linked COFs.T he realization of the linkage substitution would significantly expand the researchs cope of COFs.