Liquid metals (LMs) are used as liquid fillers in hydrophilic polymer networks to realize ultra-stretchable hydrogels as asymmetric force-sensors. The existence of liquid metals endows the hydrogel with unique features in synthetic methods and sensing applications.

Liquid metals (LMs) are receiving growing interest in modern technologies for their various advantages. This work reports using elemental sulfur to achieve nanodispersed liquid metals in bulk polymers for multifunctional LM-based materials. Ring-opening polymerization and inverse vulcanization of elemental sulfur provide many polysulfide loops and thiol groups as effective binding ligands that enable extraordinarily uniform dispersion of liquid metals (≈1 µm) in bulk matrix and improve the mechanical performance of the materials. Interestingly, the liquid-metal-embedded sulfur polymer (LMESP) materials exhibit excellent thermal-/solventprocessability and recyclability. The uniform dispersion leads to phenomenal electrical conductivity of the LMESP at a low volume percentage of LM (30 vol%), overcoming the issue of nonconductivity typically seen in insulated LM-polymer blends. Additionally, the LMESP shows resistive sensitivity toward external pressure. Furthermore, the LMESP materials exhibit an excellent self-healing ability under mild conditions via the dynamic bonds between polysulfide loops/thiol groups and liquid metals. This work clearly offers a new platform to design liquid metals and can push them for broad applications.

We propose omnidirectional reflective color filters based on metal-dielectric-metal subwavelength grating structure. By particle swarm optimization, the structural parameters of three color filters (yellow, magenta, cyan) are obtained. The optimized filters can present the same perceived specular color at unpolarized illumination for a broad range of incident angles. The reflectance curves at different incident angles keep almost invariable and the color difference is less than 6 in CIEDE2000 formula up to 45°. Angle-insensitive properties including the incident angular tolerance, azimuthal angular tolerance and the polarization effect are investigated thoroughly to construct a real omnidirectional color filter. Through the analysis of the magnetic field, the physical origin is verified that the total absorption band at specific wavelength results from the localized surface plasmon resonance responsible for the angle insensitive spectral filtering.

We reported for the first time using metal–organic framework (MOF) nanoparticles as effective nanofillers to significantly enhance the mechanical performance of hydrogels. The MOF hydrogels have been developed for drug delivery materials with high loading capacity and much extended drug releasing profiles.

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