Bionic microchannels for step lifting transpiration

Those various cross-sectional vessels in trees transfer water to as high as 100 meters,but the traditional fabrication methods limit the manufacturing of those vessels,resulting in the non-availability of those bionic microchannels.Herein,we fabricate those bionic microchannels with various cross-sections by employing projection micro-stereolithography(PμSL)based 3D printing technique.The circumradius of bionic microchannels(pentagonal,square,triangle,and five-pointed star)can be as small as 100μm with precisely fabricated sharp corners.What's more,those bionic microchannels demonstrate marvelous microfluidic performance with strong precursor effects enabled by their sharp corners.Most significantly,those special properties of our bionic microchannels enable them outstanding step lifting performance to transport water to tens of millimeters,though the water can only be transported to at most 20 mm for a single bionic microchannel.The mimicked transpiration based on the step lifting of water from bionic microchannels is also achieved.Those precisely fabricated,low-cost,various cross-sectional bionic microchannels promise applications as microfluidic chips,long-distance unpowered water transportation,step lifting,mimicked transpiration,and so on.

Self-Exfoliation of Flake Graphite for Bioinspired Compositing with Aramid Nanofiber toward Integration of Mechanical and Thermoconductive Properties

Flexible yet highly thermoconductive materials are essential for the development of next-generation flexible electronic devices.Herein,we report a bioinspired nanostructured film with the integration of large ductility and high thermal conductivity based on self-exfoliated pristine graphene and three-dimensional aramid nanofiber network.A self-grinding strategy to directly exfoliate flake graphite into few-layer and few-defect pristine graphene is successfully developed through mutual shear friction between graphite particles,generating largely enhanced yield and productivity in comparison to normal liquid-based exfoliation strategies,such as ultrasonication,high-shear mixing and ball milling.Inspired by nacre,a new bioinspired layered structural design model containing three-dimensional nanofiber network is proposed and implemented with an interconnected aramid nanofiber network and high-loading graphene nanosheets by a developed continuous assembly strategy of sol-gel-film transformation.It is revealed that the bioinspired film not only exhibits nacre-like ductile deformation behavior by releasing the hidden length of curved aramid nanofibers,but also possesses good thermal transport ability by directionally conducting heat along pristine graphene nanosheets.

Single-material Solvent-sensitive Fluorescent Actuator from Carbon Dots Inverse Opals Based on Gradient Dewetting

A novel solvent-sensitive fluorescent actuator with reversibility has been obtained from carbon dots （CDs） inverse opals, which is prepared via infiltrating CDs solution into the interstice of colloidal crystal template, thermal polymerization of CDs materials and removing the colloidal template. The as-prepared CDs inverse opal actuator shows a bending angle of 75° in 10.2 s, bending rate of 7.35 （°）.s-1. In particular, the fluorescence intensity of the films varies during the actuating process. The actuating behavior is attributed to the inhomogeneous swelling/shrinking of the film, which originates from the gradient dewetting by solvent evaporation and hydrogen-bonding interaction between the solvent molecules and oxygen/hydrogen ions of CDs side chain. The CDs inverse opal actuator has the advantages of quick response, good repeatability and strong fluorescence, which gives an important insight into the design and manufacture of novel and advanced solvent-actuators.

Fast processing nylon mesh by surface diffuse atmospheric plasma for large-area oil/water separation

In recent years,numerous studies have been reported for oil/water separation,such as superoleophilic materials for oil absorption and underwater superoleophobic membranes for continuous separation.However,for the recovery of oil slick pollution on near-shore ocean surface caused by various reasons,large area and fast availability of used materials are needed to be considered.Herein,we report an efficient and environmentally friendly method to fast process nylon mesh by surface diffuse atmospheric plasma(SDAP)for large-area oil/water separation.Nylon mesh is funcionalized by atmospheric plasma to generate micro/nano composite structures on the surface,resulting in superhydrophilicity and underwater superoleophobicity within only seconds.The pre-wetted modified nylon mesh can achieve high efficiency(>99.9%)and circulating water flux(~30,000 L·m^(-2)·h^(-1)),with high intrusion pressure(~3 kPa)and universality in oil/water separation.Regular plasma unconditionally generated in the atmosphere with the merit of efficiently functionalizing surface has the potential of large-area materials treatment.This study might take one step further for large-area industrial oily wastewater recovery and even oil slicks collection in near-shore water bodies.

Bioinspired Three-Dimensional Nanoporous Membranes for Salinity-Gradient Energy Harvesting

CONSPECTUS:Salinity-gradient energy represents a widespread,clean,environmentally friendly,and sustainable source of renewable energy,which has attracted great attention in the past years.To harness this energy,interdisciplinary efforts from chemistry,materials science,environmental science,and nanotechnology have been made to develop efficient and low-cost approaches and materials for energy conversion.Conventional reverse electrodialysis(RED)systems are generally based on ion-exchange membranes,which usually suffer from ineffective mass transport,high membrane resistance,limited pore size,and concentration polarization,resulting in low output power density and poor energyconversion efficiency.As one promising material,nanofluidic channels with their unique transport properties,which can be attributed to nanoconfinement effect,enable highperformance reverse electrodialysis to efficiently harvest salinity-gradient energy.Due to the unique porous architectures,three-dimensional(3D)nanoporous membranes demonstrate great potential for harvesting salinity-gradient power.It is generally known that the porous membranes can be prepared by many methods;however,there are some shortcomings such as high costs,poor ion conductance,and fragility limiting the practical application.Several simple and versatile approaches to lowcost fabrication of 3D nanoporous membranes have been developed in recent years.For example,self-assembly provides an effective route of constructing functional materials and organizing them into 3D architectures.In this Account,we mainly review our recent progress in the design and fabrication of bioinspired 3D nanoporous membranes for salinity-gradient energy harvesting.First,we give a brief introduction to bioinspired nanochannel membranes(BNMs)with diverse structural dimensions,and nanofluidic channel membranes may lead to technological breakthroughs and thus act as an emerging platform for harvesting salinity-gradient energy.Subsequently,we discuss the typical preparation approaches for bioinspired 3D nanoporous membranes.To tackle the bottlenecks of the conventional membrane-based power generator and extrapolate single-channel devices to macroscopic materials,our group have developed a series of 3D nanoporous membranes for power generation via various simple and versatile methods.We highlight the design and fabrication of several types of 3D nanoporous membranes,i.e.,heterogeneous and homogeneous membranes,with tunable surface charge and porosity.The proof-of-concept demonstration of bioinspired 3D porous membranes shows that these nanofluidic platforms have the potential to overcome the selectivity-permeability trade-off and have impressive osmotic-energy-harvesting performance.Specifically,the scale-up Janus 3D porous membranes maintained high selectivity and rectified current in a hypersaline environment,which benefitted effective energy conversion and high output power density when seawater and river water were mixed.Finally,we give an outlook for future challenges and perspectives on the development of 3D nanofluidics for salinity-gradient energy conversion.We expect that this Account will spark further efforts on the development of bioinspired 3D nanoporous membranes for large-scale(typical side length of more than 10 cm)energy conversion and new opportunities for the applications in water desalination,dialysis,and ionic circuitries.

Calcium-magnesium-alumina-silicate(CMAS)resistant high entropy ceramic(Y_(0.2)Gd_(0.2)Er_(0.2)Yb_(0.2)Lu_(0.2))_(2)Zr_(2)O_(7) for thermal barrier coatings

A novel high-entropy material,(Y_(0.2)Gd_(0.2)Er_(0.2)Yb_(0.2)Lu_(0.2))_(2)Zr_(2)O_(7)was successfully synthesized by the solid state reaction method and spark plasma sintering,and investigated as a promising thermal barrier coating material.Rare-earth elements were distributed homogeneously in the pyrochlore structure.It was found that the prepared high-entropy ceramic maintains pyrochlore structure at the temperature up to 1600℃,and it possesses a similar thermal expansion coefficient(10.2×10^(−6)K^(−1) at 25-900℃)to that of YSZ,low thermal conductivity(<0.9 W m^(-1)K^(−1) at 100-1000℃)and good CMAS resistance(infiltration depth is 22μm after annealed at 1300℃for 24 h).The corrosion process was investigated,and RE elements distributing homogeneously in(Y_(0.2)Gd_(0.2)Er_(0.2)Yb_(0.2)Lu_(0.2))_(2)Zr_(2)O_(7)show different diffusion rates in CMAS.RE^(3+) with a larger radius(closer to Ca^(2+))is easier to react with CMAS to form an apatite phase.

High-efficiency,self-grinding exfoliation of small graphene nanosheets from microcrystalline graphite driven by microbead milling as conductive additives

Direct mass exfoliation of graphene from bulk graphite with high yield and productivity for commercial applications is challenging.This work proposes self-grinding exfoliation using the mutual shear friction of graphite particles to fabricate graphene from microcrystalline graphite.The concept is implemented using microbeads as the grinding medium to drive the shear friction between graphite nanocrystals in a high-concentration paste.The proposed approach substantially improves graphene yield from 6.3% to 100% and simultaneously generates a record productivity of 7.5 g h^(-1)L^(-1),achieving total graphite-to-graphene conversion on the kilogram scale.The as-prepared graphene nanosheets have an average lateral size of 298 nm and the same C/O atomic ratio as the pristine graphite.In addition,the well-exfoliated,small nanosheets display good electrical conductivity and exhibit significant potential as conductive additives that improve the specific capacity and cyclic stability of Li-ion batteries better than commercial carbon-based conductive particles.

Fluorescence Retention of Organosilane-polymerized Carbon Dots Inverse Opals in CuCl Suspension

A novel and fluorescence retention inverse opal has been achieved from organosilane-polymerized carbon dots（SiCDs）, which is prepared via infiltrating SiCD solution into the interstice of photonic crystal（PC） template, low temperature treatment, heating polymerization and removing the colloidal template. The as-prepared SiCD inverse opals demonstrate close-cell structure, which is completely different from conventional open-cell structure. Then the fluorescence signal of as-prepared sample keeps almost unchanged in CuCl suspension while the fluorescence of SiCD solution can be quenched by CuCl suspension through an effective electron transfer process. This phenomenon can be attributed to the combined effect of high hydrostatic pressure in the pore structure, stable crosslinking network and fluorescence enhancement by PC structure. The SiCD inverse opals have advantages of unique close-cell structure, easy preparation and good repeatability that give an important insight into the design and manufacture of novel and advanced optical devices.