Bioinspired film with tunable wettability is developed for liquid manipulation based on a lubricant-infused shape-memory graphene sponge.

Functional materials with wettability of specific surfaces are important for many areas. Here, a new lubricant‐infused elastic inverse opal is presented with tunable and visually “self‐reporting” surface wettability. The elastic inverse opal films are used to lock in the infused lubricating fluid and construct slippery surfaces to repel droplets of various liquids. The films are stretchable, and the lubricating fluid can penetrate the pores under stretching, leaving the surface layer free of lubrication; the resultant undulating morphology of the inverse opal scaffold topography can reversibly pin droplets on the fluidic film rather than the solid substrate. This mechanical stimulation process provides an effective means of dynamically tuning the surface wettability and the optical transparency of the inverse opal films. In particular, as the adjustments are accompanied by simultaneous deformation of the periodic macroporous structure, the inverse opal films can self‐report on their surface status through visible structural color changes. These features make such slippery structural color materials highly versatile for use in diverse applications.

Surgical mask is recommended by the World Health Organization for personal protection against disease transmission. However, most of the surgical masks on the market are disposable that cannot be self-sterilized for reuse. Thus, when confronting the global public health crisis, a severe shortage of mask resource is inevitable. In this paper, a novel low-cost electrothermal mask with excellent self-sterilization performance and portability is reported to overcome this shortage. First, a flexible, ventilated, and conductive cloth tape is patterned and adhered to the surface of a filter layer made of melt-blown nonwoven fabrics (MNF), which functions as interdigital electrodes. Then, a graphene layer with premier electric and thermal conductivity is coated onto the MNF. Operating under a low voltage of 3 V, the graphene-modified MNF (mod-MNF) can quickly generate large amounts of heat to achieve a high temperature above 80 °C, which can kill the majority of known viruses attached to the filter layer and the mask surface. Finally, the optimized graphene-modified masks based on the mod-MNF filter retain a relatively high particulate matter (PM) removal efficiency and a low-pressure drop. Moreover, the electrothermal masks can maintain almost the same PM removal efficiency over 10 times of electrifying, suggesting its outstanding reusability.

absorption with noticeable photothermal conversion efficiency have been developed for SSG, [7,8] plasmonic metal, [9][10][11][12][13] semiconductors, [14][15][16][17] and carbon-based materials. [18][19][20][21] However, the high-cost and complex manufacturing processes make it hard to prepare on a large-scale. [22] And the accumulation of salt deposits on the photothermal layers results in a sharp decline in SSG performance, thus lacking sustainability and recyclability. [23] Therefore, the SSG are yet far from industrialization that requires low-cost, scalable, and reusable photothermal materials.Carbonization of rampant plants into carbon materials by the high-temperatureinduced pyrolysis provides an alternative solution to these problems, but it still has great challenges. [24] With the development of this technology, a variety of plants have been explored to synthesis different photothermal layers. [25][26][27][28][29] For instance, Xu et al. [28] demonstrated mushrooms as a solar steam generator for the first time. The unique natural structure of mushroom, porous context, and fibrous stipe, make the conversion efficiency of natural and carbonized mushrooms achieve 62% and 78% under 1 sun illumination. Fang et al. [29] found that the unique macroscopic cone shape and hierarchical porous structures of the carbonized lotus seedpods resulted in an evaporation rate and the corresponding evaporation efficiency under 1 sun irradiation of 1.30 kg m −2 h −1 and 86.5%, respectively. The special structure of plant stem is conducive to improving the SSG ability, which is due to the fact that the plant stem can transport water and other nutrients to the upper layer during the whole plant growth process. [30] However, the prices of the current plants, such as mushroom, lotus seedpods, still need to be further cut down (the cost comparison is shown in Table S1 in the Supporting Information). It is of great significance to explore more abundant and low-cost plants for carbonization. Moreover, the mechanical strength and surface of the plants are destroyed by the high temperature during the carbonization process. It is still a big challenge to uniformly and stably deposit the carbonized species on substrates or assemble them to self-stand films at a large scale. [31][32][33] Most importantly, the steam generation rate and evaporation efficiency are yet to be further increased. Solar steam generation (SSG) based on the photothermal effect has beenconsidered to be a promising avenue for freshwater production. However, the fabrication of highly-efficient photothermal layers, at large-scale and low-cost is still a challenge, hindering practical applications. Herein, it is demonstrated that carbonized towel-gourd sponges (CTGS) are excellent photothermal materials. And a capillarity-driven interfacial self-coating method is developed to prepare the super-hydrophilic CTGS/paper photothermal layer. The SSG device based on the CTGS/paper exhibits a high evaporation rate of 1.53 kg m −2 h −1 with an efficiency of 95.9% under 1 sun i...

In this work, we demonstrate the fabrication of photonic crystal patterns with controllable morphologies and structural colors utilizing electrohydrodynamic jet (E-jet) printing with colloidal crystal inks. The final shape of photonic crystal units is controlled by the applied voltage signal and wettability of the substrate. Optical properties of the structural color patterns are tuned by the self-assembly of the silica nanoparticle building blocks. Using this direct printing technique, it is feasible to print customized functional patterns composed of photonic crystal dots or photonic crystal lines according to relevant printing mode and predesigned tracks. This is the first report for E-jet printing with colloidal crystal inks. Our results exhibit promising applications in displays, biosensors, and other functional devices.