Qingdong Zhang

From drug to adhesive: a new application of poly(dihydropyrimidin-2(1H)-one)s via the Biginelli polycondensation

The reactions for polymer synthesis should be simple and efficient using easily available raw materials. A new difunctional monomer containing benzaldehyde and beta-keto ester groups (monomer AB) has been successfully prepared on a medium scale, and the corresponding poly(dihydropyrimidin-2(1H)-one)s (DP ∼84) can be synthesized via the Biginelli polycondensation in a short time (∼1 h). The in situ generated polycondensates could glue two metal sheets, demonstrating an interesting metal bonding property which cannot be observed in small molecules. The optimized multifunctional monomers (AB2, A2B2 monomers) were subsequently used for the in situ polycondensation between metal sheets, and metal bonding strength could be improved to the similar level of commercial cyanoacrylate glue. Since the monomers could be easily prepared on a large scale and the polymerization could be simply performed, the Biginelli polycondensation might have potential as a new strategy to synthesize new functional polymers.

Fluorescent polymeric nanoparticles with ultra-low CMC for cell imaging

A novel amphiphilic copolymer is facilely prepared through radical polymerization and subsequent ring-opening crosslinking based on poly(ethylene glycol) monomethyl ether methacrylate, glycidyl methacrylate, and amino-terminated aggregation-induced emission dye. Such a cross-linked polymer can self-assemble into nanoparticles with ultra-low critical micelle concentration (CMC), intense red fluorescence, and excellent biocompatibility for cell imaging.

Nanocomposite Deposited Membrane for Oil-in-Water Emulsion Separation with in Situ Removal of Anionic Dyes and Surfactants

The decontamination of various pollutants including oils, organic dyes, and surfactants from water is an unprecedented issue throughout the world. A facile filtration process for in situ multifunctional water purification by employing a low-cost and easy-made catechol-polyethylenimine (PEI) nanocomposite deposited membrane has been designed. In combination with the intrinsic hydrophilicity of amino-rich groups, the resultant membrane possesses superhydrophilicity and underwater superoleophobicity, which is simultaneously advantageous for capturing anionic pollutants due to the electrostatic interaction. Such membrane can be successfully used for sundry surfactant-stabilized oil-in-water emulsions separation and pH-controllable removal of water-soluble dyes and the remaining surfactants at the same time. The excellent characteristics, i.e., fabrication protocol that is easy to scale up, better alkaline resistance, selectively controllable removal ability of anionic dyes, and surfactants with unaltered adsorption performance over 30 consecutive adsorption-desorption-washing cycles, will facilitate its versatility and practicability in environmental remediation and wastewater purification.

Polyacrylamide-Polydivinylbenzene Decorated Membrane for Sundry Ionic Stabilized Emulsions Separation via a Facile Solvothermal Method.

Aiming to solve the worldwide challenge of stabilized oil-in-water emulsion separation, a PAM-PDVB decorated nylon membrane is fabricated via a facile solvothermal route in our group. The main composition is PAM, while the PDVB plays a role as cross-linker in order to improve the interaction between the polymer and the substrate. By the combination of the superhydrophilic and underwater superoleophobic wettability of the PAM polymer with the micropore size of the substrate, the as-prepared material is able to achieve the separation of various stabilized oil-in-water emulsions including cationic type, nonionic type, and anionic type. Compared with previous works, the emulsions used in this case are more stable and can stay for several days. Besides, the solvothermal method is facile, cost saving, and relatively environmentally friendly in this experiment. Moreover, the PAM-PDVB modified membrane exhibits excellent pH stability, recyclability, and high separation efficiency (above 99%), which can be scaled up and used in the practical industrial field.

Lighting up the PEGylation agents via the Hantzsch reaction

Fluorescent PEGylation agents have been facilely synthesized through the Hantzsch reaction. Different from other methods, a protein reactive group has been linked at the PEG chain ends through a Hantzsch ester, which is inherently fluorescent, to in situ generate fluorescent protein-reactive PEGs. Therefore, after conjugation with a protein, the multifunctional polymers can not only act as a protective umbrella to the protein like normal PEGylation agents, but also introduce new functions to the protein conjugates to achieve multifunctional protein conjugates. The multifunctional protein conjugates are directly visible under UV and retain nearly intact bioactivity, preliminarily suggesting the new application of the ‘old’ Hantzsch reaction in other areas (polymer chemistry, chemical biology) outside organic chemistry.

Recycling of PE glove waste as highly valuable products for efficient separation of oil-based contaminants from water

In this study, we prepared a highly efficient PE coated mesh by simply using recycled PE gloves as raw materials. This mesh showed high separation efficiency and large flux when separating water from different types of oil/water mixtures. It also exhibited excellent stability and maintained high hydrophobicity and super-oleophilicity properties after being reused at least thirty times. In view of the advantages of this as-prepared mesh, it will contribute to reduce white pollution from used PE materials and will have wide applications in wastewater treatment utilizing oil/water separation.

Fabrication of robust mesh with anchored Ag nanoparticles for oil removal and in situ catalytic reduction of aromatic dyes

Effective removal of oils and aromatic dyes from water is of critical, global importance for environmental and water remediation. A green and facile electro-deposition approach to anchor Ag nanoparticles (NPs) onto the surface of a mesh support coated with polydopamine is proposed. The Ag NPs with high surface energy and specific surface area endow the resultant mesh with superhydrophilicity/underwater superoleophobicity as well as superior catalytic reduction ability of aromatic dyes. The mesh with anchored Ag NPs exhibits excellent oil removal capacity and in situ catalytic performance in the reduction of sundry aromatic dyes. Furthermore, the as-prepared mesh can be readily reused or stored in air even under harsh conditions because of its robust immobilization capability and strong resistance to oxidation. These versatile abilities integrated with a facile fabrication process provide promising potential for cost-effective water purification.

Thermo‐Driven Controllable Emulsion Separation by a Polymer‐Decorated Membrane with Switchable Wettability

A thermoresponsive Poly(N-isopropylacrylamide) (PNIPAAm)-modified nylon membrane was fabricated via hydrothermal route. Combining rough structure, proper pore size, and thermoresponsive wettability, the membrane can separate at least 16 types of stabilized oil-in-water and water-in-oil emulsions at different temperatures. Below the LCST (ca. 25 °C), the material exhibits hydrophilicity and underwater superoleophobicity, which can be used for the separation of various kinds of oil-in-water emulsions. Above the LCST (ca. 45 °C), the membrane shows the opposite property with high hydrophobicity and superoleophilicity, and it can then separate stabilized water-in-oil emulsions. The material exhibits excellent recyclability and high separation efficiency for various kinds of emulsions and the hydrothermal method is facile and low-cost. The membrane shows good potential in real situations such as on-demand oil-spill cleanup, industrial wastewater treatment, remote operation of oil/water emulsion separation units, and fuel purification.

A versatile CeO2/Co3O4 coated mesh for food wastewater treatment: Simultaneous oil removal and UV catalysis of food additives

Food waste water is one of the most urgent environmental problems for the close connection between food and our daily life. Herein, we use a simple hydrothermal method to prepare a highly efficient catalyst-CeO2/Co3O4 compound on the stainless steel mesh, aiming for food waste water treatment. Possessing the superhydrophilic property and catalytic ability under ultraviolet light, CeO2/Co3O4 coated mesh has successfully processed three representative contaminants in food wastewater, which are soybean oil (food oil), AR (food dye) and VA (food flavor) simultaneously with an one-step filtration. Besides, the mesh is stable in a wide pH range and performs well in reusability. Therefore, such a multifunctional material with simple preparation method, high processing efficiency and facile operation shows a promising prospect for practical production and application for food wastewater treatment.

Facile fabrication of hydrogel coated membrane for controllable and selective oil-in-water emulsion separation

The facile fabrication of a hydrogel-networks coated membrane for efficient oil-in-water emulsion separation was successfully achieved through the photo-initiated free radical polymerization of 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS). Due to the combination of the special wettability of the PAMPS hydrogel with the microscale multi-porous structure of the substrate, such a membrane is able to achieve the separation of sundry surfactants stabilized oil-in-water emulsions with high separation efficiency, large permeation flux and excellent stability. In particular, the PAMPS hydrogel coated membrane exhibits selective separation for cationic and nonionic types of surfactants stabilized emulsions via hydrogen bond interactions. The fabrication protocol is facile, cost-efficient and environmentally friendly, which can be scaled up to facilitate its practicability in sewage remediation.