Lu Shao

An overview of the engineered graphene nanostructures and nanocomposites

This critical review focuses on the property analysis of graphene and graphene nanocomposites (GNCs) and their demonstrated superior performances in energy storage and conversion, electrochemical- and bio-sensing, environmental remediation and flame retardant application and atomic thickness membrane separation. The performances of graphene and GNCs are strongly dependent on their chemical component, synthetic method, nanoscale morphology, and assembling structure of the hybrids. The current progress in supercapacitor energy storage density, solar cell power conversion efficiency, thermoelectric energy conversion efficiency, electrochemical sensing capability, biosensor sensitivity, heavy metal adsorption capacity and efficiency, photocatalytic degradation rate of organic dye, flame retardant polymer nanocomposites, graphene and porous graphene membranes is discussed with detailed examples through extensive analysis of the literature.

Advanced micro/nanocapsules for self-healing smart anticorrosion coatings

Smart self-healing coatings for corrosion protection of metallic substrates (steel, magnesium, and aluminium, and their alloys) have attracted tremendous interest due to their capability to prevent crack propagation in the protective coatings by releasing active agents from micro/nanocapsules, that is, micro/nano particles consisting of a coating layer or a shell (micro/nanocontainers) and core material (solids, droplets of liquids or gases), in a controllable manner. This paper aims to give a concise review on the most recent advances in preparing micro/nanocapsules based on different types of micro/nanocontainers, i.e., organic polymer coatings, inorganic clays, mesoporous silica nanoparticles, polyelectrolyte multilayers, etc. for smart coatings with self-healing properties. The state-of-the-art design and preparation of micro/nanocapsules are highlighted with detailed examples.

Mussel-Inspired Hybrid Coatings that Transform Membrane Hydrophobicity into High Hydrophilicity and Underwater Superoleophobicity for Oil-in-Water Emulsion Separation

We first report here mussel-inspired, hybrid coatings formed in a facile manner via simultaneous polymerization of mussel-inspired dopamine and hydrolysis of commercial tetraethoxysilane in a single-step process. The hybrid coatings can firmly adhered on hydrophobic polyvinylidene fluoride (PVDF) substrate, and the hydrophilicity of the coating can be tuned by adjusting silane concentration. The reason for the changed hydrophilicity of the coating is disclosed by a series of characterization, and was applied to rationally design optimized hybrid coatings that transform commercial PVDF microfiltration (MF) membrane hydrophobicity into high hydrophilicity with excellent water permeability and underwater superoleophobicity for oil-in-water emulsion separation. The PVDF MF membrane decorated with optimized coatings has ultrahigh water flux (8606 L m(-2) h(-1) only under 0.9 bar, which is 34 times higher than that of pristine membrane), highly efficient oil-in-water emulsion separation ability at atmospheric pressure (filtrate flux of 140 L m(-2) h(-1)) and excellent antifouling performance. More importantly, these membranes are extremely stable as underwater superoleophobicity are maintained, even after rigorous washings or cryogenic bending, disclosing outstanding stability. The simplicity and versatility of this novel mussel-inspired one-step strategy may bridge the material-induced technology gap between academia and industry, which makes it promising for eco-friendly applications.

Mussel-inspired tailoring of membrane wettability for harsh water treatment

Novel hybrid coatings with excellent wettability are architecturally constructed on the surfaces of different types of separation membranes via simultaneous polymerization of mussel-inspired dopamine and hydrolysis of commercially available and low-cost silane through a highly efficient one-step approach. After coating with the designed hybrid coatings, the ultrafiltration (UF) membranes possess high hydrophilicity and excellent dry storage ability while the microfiltration (MF) membranes are endorsed with superhydrophilicity and underwater superoleophobicity. Such unique UF and MF membranes can be deployed for treating protein-rich water with drastically enhanced functions and separating oily water (oil-in-water emulsion) under atmospheric conditions with ultrahigh water flux and superior antifouling abilities. This versatile strategy to tailor membrane surface wettability paves the way for separation membranes to be used in harsh water environmental remediation and greatly stimulates the rapid development of mussel-inspired pDA based hybrid materials for advanced applications.

A novel mussel-inspired strategy toward superhydrophobic surfaces for self-driven crude oil spill cleanup

The current available superhydrophobic modification techniques that utilize mussel-inspired polydopamine (pDA) to construct hierarchical structures require the addition of nanoparticles or the usage of a high concentration of dopamine. These requirements are expensive and therefore lower the application efficiency. Herein, for the first time, a superhydrophobic fabric was prepared by a novel and simple mussel-inspired strategy with a much lower concentration of dopamine without any additional nanoparticles. Folic acid (FA) was first applied to a surface to induce the formation of rough pDA coatings with hierarchical structures. These hierarchical structures can be readily controlled by adjusting FA concentration or coating duration. After octadecylamine (ODA) chemical manipulation, the obtained fabric exhibited water contact and rolling off angles of about 162° and 7°, respectively, indicating that it was endowed with superhydrophobicity. Importantly, the superhydrophobic fabric can withstand continuous and drastic 3.5 wt% NaCl solution rinses and repeated tearing with an adhesive tape more than 30 times, suggesting that it has excellent durability. This novel mussel-inspired strategy can facilely and cost-effectively realize superhydrophobic manipulation and tailoring of materials. Moreover, an energy-saving and highly-efficient mini boat fabricated from our novel superhydrophobic fabric was utilized for self-driven oil spill cleanup. The boat can automatically recycle crude oil spills while floating freely on water with a cleanup rate of crude oil spill up to 97.1%, demonstrating great potential in environmental remediation. The novel strategy designed in this study will inspire the fast development of mussel-inspired superhydrophobic materials for applications in various fields.

Influence of ultrasonic treatment on the characteristics of epoxy resin and the interfacial property of its carbon fiber composites

To enhance the interfacial property between a carbon fiber and epoxy matrix, an ultrasonic technique was used to treat the resin liquid and the impregnated fibers respectively. The effects of the treatments on the characteristics of the resin system and the fiber surface, as well as fiber/matrix interfacial bonding strength, were analyzed and discussed. The results indicated ultrasonic treatments significantly decreased the viscosity and surface tension of the resin system, and increased the wettability and the oxygen content of the fiber surface due to the ultrasonic cavitation effects. Microbond tests revealed much more increase of interfacial shear strength when the ultrasound was applied to the impregnated fibers, and combination failures of interface and matrix layer were observed from the pulled-out fiber surface.

Highly regenerable alkali-resistant magnetic nanoparticles inspired by mussels for rapid selective dye removal offer high-efficiency environmental remediation

Most recently, polydopamine (PDA) and its hybrid nanomaterials have been developed as promising adsorbents to remove organic dyes. However, PDA-based adsorbents are typically limited by a poor alkali resistance, lack of selective adsorption capacity and unsatisfactory recyclability. Herein, novel PDA-based magnetic nanoparticles are fabricated for the first time via the simultaneous incorporation of PDA and poly(ethylenimine) (PEI) on Fe3O4 nanoparticles simply in one step to overcome almost all the disadvantages of “traditional” PDA adsorbents. The constructed PDA-based magnetic nanoparticles have an ultrathin shell layer (only about 3 nm, much thinner than that of other PDA adsorbents) and can withstand strong alkaline solutions (0.1 M NaOH, pH = 13), exhibiting an excellent alkali resistance. Remarkably, the nanoparticles show superior performance in smart and fast selective removal (>95% in just five minutes) of anionic dyes from dye mixtures and can maintain their high efficiency (>90%) even after 10 cycles, indicating the unprecedented selective adsorption capacity and the desirable recyclability. The adsorption process follows pseudo-second order reaction kinetics, as well as the Langmuir isotherm, indicating that anionic dyes are monolayer adsorbed on the hybrid by electrostatic interaction. In particular, the facile regeneration of the novel composite nanoparticles can be accomplished within only several minutes, demonstrating an excellent regeneration ability. Our study can provide new insights into utilizing mussel-inspired materials for environmental remediation and creating advanced magnetic materials for various promising applications.

Pushing CO2-philic membrane performance to the limit by designing semi-interpenetrating networks (SIPN) for sustainable CO2 separations

Semi-interpenetrating network (SIPN) membranes with unprecedentedly high CO2 permeability were designed and synthesized simply through one-step, UV-induced radical polymerization. The in situ embedment of linear polyethylene glycol as a “CO2 transport promoter” in membranes can dramatically enhance both CO2 solubility and diffusivity to push SIPN membrane performance beyond Robesons upper bound line (2008). This extremely facile performance-manipulating strategy establishes our CO2-philic SIPN membranes as an exciting platform for sustainable CO2 separations.

Designing multifunctional 3D magnetic foam for effective insoluble oil separation and rapid selective dye removal for use in wastewater remediation

Highly-efficient separating materials, which can simultaneously remove oil from water and adsorb water-soluble contaminants like dyes, are in high demand for wastewater treatment. Herein, a magnetic, multifunctional melamine foam (MF) containing Fe3O4 nanoparticles, poly(sulfobetaine methacrylate) (PSBMA) and polydopamine (PDA) was fabricated via a simple mussel-inspired one-pot process, which not only can separate oil/water mixtures and emulsions but also has cationic-dye selective separation abilities. The addition of poly(sulfobetaine methacrylate) (PSBMA) allows immobilization to bind Fe3O4 nanoparticles tightly on the surface of the melamine foam skeleton so as to endow the 3D foam with superoleophobicity underwater, as well as providing active sites for the adsorption of soluble dyes in water. The special material synergy makes the resultant magnetic MF@Fe3O4@PDA/PSBMA foam quickly absorb cationic dyes and allows for the selective removal (in 2 minutes) of cationic dyes from dye mixtures with high efficiency (>96%), high stability and flexibility even after 10 cycles, when driven by a magnet. Furthermore, the developed 3D magnetic foam is able to separate oil–water mixtures in highly acidic, alkaline, and salty environments. Our strategy may open a new avenue to obtain high-performance 3D magnetic assemblies for wastewater remediation.

Simply realizing “water diode” Janus membranes for multifunctional smart applications

A facile strategy for the preparation of multifunctional Janus membranes (JMs) was proposed, and excellent controllability of the multifunctional JMs was demonstrated in water collection, lossless transportation, decontamination, and on-off control. This novel strategy will accelerate the evolution of JMs from a scientific concept to usable materials for the “real” world.