Cheng Wang

Bio: Cheng Wang is an academic researcher from Nanjing University of Science and Technology. The author has contributed to research in topics: Oxide & Electrolyte. The author has an hindex of 7, co-authored 13 publications receiving 258 citations.

Extremely Stretchable, Self-Healable Elastomers with Tunable Mechanical Properties: Synthesis and Applications

Abstract: Stretchable and autonomously self-healable elastomers with wide-ranging tunable mechanical properties have attracted increasing attention in various industries. To date, it continues to be a huge challenge to synthesize self-healing elastomers integrating extreme stretchability, relatively high mechanical modulus, and autonomous and rapid self-healing capability. Herein, we propose a novel covalent/supramolecular hybrid construction strategy, in which the covalent cross-links are responsible for providing high modulus and elasticity, while supramolecular cross-links realize extreme stretchability and rapid self-healing under room temperature depending on the ultrafast exchange kinetics of metal–ligand motifs and multicoordination modes. The representative polyurea hybrid elastomer, CSH-PPG-Zn-0.25, can be stretched more than 180× its original length with the highest Young’s modulus (1.78 ± 0.08 MPa) among reported ultrastretchable materials. CSH-PPG-Zn-0.25 can fully restore mechanical properties of compl...

Molecular engineering of a colorless, extremely tough, superiorly self-recoverable, and healable poly(urethane-urea) elastomer for impact-resistant applications.

Abstract: Polyurethane or polyurea elastomers with superb mechanical strength and toughness, good self-recoverability and healable characteristics are of key significance for practical applications. However, some mutually exclusive conflicts among these properties make it challenging to optimize them simultaneously. Herein, we report a facile strategy to fabricate a colorless healable poly(urethane–urea) elastomer with the highest reported mechanical toughness and recoverable energy dissipation capability (503.3 MJ m−3 and 37.3 MJ m−3 recovered after 7× stretching). These results were achieved via implanting a large number of irregularly arranged urea H-bonds into units of hard domains of weak and soft, self-healing polymer, which led to a dramatic increase in the Young's modulus, tensile strength, toughness, and fracture energy, while maintaining dynamic adaptiveness and responsiveness. Similar to other external stimuli, such as heat, light, or electricity, etc., trace solvent is capable of dissociating noncovalent crosslinks, promoting the mobility of polymer chains surrounding the fracture surface, and thus endowing the elastomer with healability. Impressively, this elastomer possessed outstanding impact-resistance and energy-absorbing ability, even under relatively high temperature. Moreover, it recovered this functionality even after severe deformation or accidental mechanical damage.

Facile Synthesis of Smart Nanocontainers as Key Components for Construction of Self-Healing Coating with Superhydrophobic Surfaces.

Abstract: SiO2-imidazoline nanocomposites (SiO2-IMI) owning high loading capacity of corrosion inhibitor, 1-hexadecyl-3-methylimidazolium bromide (HMID), and a special acid/alkali dual-stimuli-accelerated release property have been synthesized via a one-step modified Stober method. SiO2-IMI were uniformly distributed into the hydrophobic SiO2 sol to construct “host”-“guest” feedback active coating with a superhydrophobic surface (SiO2-IMI@SHSC) on aluminium alloy, AA2024, by dip-coating technique. SiO2-IMI as “guest” components have good compatibility with “host” sol-gel coating, and more importantly, once localized corrosion occurs on the surface of AA2024, SiO2-IMI can simultaneously respond to the increase in environmental pH around corrosive micro-cathodic regions and decrease in pH near micro-anodic regions, promptly releasing HMID to form a compact molecular film on the damaged surface, inhibiting corrosion spread and executing a self-healing function. The scanning vibrating electrode technique (SVET) was applied to illustrate the suppression process of cathodic/anodic corrosion activities. Furthermore, benefiting from the superhydrophobic surface, SiO2-IMI@SHSC remained its protective ability after immersion in 0.5 M NaCl solution for 35 days, which is far superior to the conventional sol-gel coating with the same coating thickness. The facile fabrication method of SiO2-IMI simplifies the construction procedure of SiO2-IMI@SHSC, which have great potential to replace non-environmental chromate conversion coatings for practical use.

Highly stretchable, non-flammable and notch-insensitive intrinsic self-healing solid-state polymer electrolyte for stable and safe flexible lithium batteries

Abstract: Solid-state polymer electrolytes (SPEs) with superior self-healing capacity are urgently required for next-generation flexible energy storage devices Herein, a highly stretchable (extensibility > 4000% and stress > 130 kPa), non-flammable and notch-insensitive intrinsic self-healing solid-state polymer electrolyte (SHSPE) was prepared based on the combination of a poly(HFBM-co-SBMA) network, imidazole-based ionic liquid (EMI–TFSI) and LiTFSI The incorporation of the imidazole cation and fluorine atom contributed to the formation of supramolecular bonds (ion–dipole interactions) inside the electrolyte framework, thus endowing SHSPE with prominent self-healing ability (recovery time 200 g) The as-assembled Li/SHSPE3/LiFePO4 battery delivered a high discharge capacity of 1448 mA h g−1 at 02C, and its capacity retention ratio reached 82% after 100 cycles with a coulombic efficiency of 97% In particular, the mechanical properties and conductivity of SHSPE3 could fully recover after repeated damage, conferring the derived soft-pack battery excellent anti-fatigue capability The use of intrinsic self-healing principles in the field of SPEs provides new insight for developing reliable and safe flexible electronic devices

Mechanized Silica Nanoparticles: A New Frontier in Theranostic Nanomedicine

Abstract: Medicine can benefit significantly from advances in nanotechnology because nanoscale assemblies promise to improve on previously established therapeutic and diagnostic regimes. Over the past decade, the use of delivery platforms has attracted attention as researchers shift their focus toward new ways to deliver therapeutic and/or diagnostic agents and away from the development of new drug candidates. Metaphorically, the use of delivery platforms in medicine can be viewed as the "bow-and-arrow" approach, where the drugs are the arrows and the delivery vehicles are the bows. Even if one possesses the best arrows that money can buy, they will not be useful if one does not have the appropriate bow to deliver the arrows to their intended location. Currently, many strategies exist for the delivery of bioactive agents within living tissue. Polymers, dendrimers, micelles, vesicles, and nanoparticles have all been investigated for their use as possible delivery vehicles. With the growth of nanomedicine, one can envisage the possibility of fabricating a theranostic vector that could release powerful therapeutics and diagnostic markers simultaneously and selectively to diseased tissue. In our design of more robust theranostic delivery systems, we have focused our attention on using mesoporous silica nanoparticles (SNPs). The payload "cargo" molecules can be stored within this robust domain, which is stable to a wide range of chemical conditions. This stability allows SNPs to be functionalized with stimulus-responsive mechanically interlocked molecules (MIMs) in the shape of bistable rotaxanes and psuedorotaxanes to yield mechanized silica nanoparticles (MSNPs). In this Account, we chronicle the evolution of various MSNPs, which came about as a result of our decade-long collaboration, and discuss advances in the synthesis of novel hybrid SNPs and the various MIMs which have been attached to their surfaces. These MIMs can be designed in such a way that they either change shape or shed off some of their parts in response to a specific stimulus, such as changes in redox potential, alterations in pH, irradiation with light, or the application of an oscillating magnetic field, allowing a theranostic payload to be released from the nanopores to a precise location at the appropiate time. We have also shown that these integrated systems can operate not only within cells, but also in live animals in response to pre-existing biological triggers. Recognizing that the theranostics of the future could offer a fresh approach to the treatment of degenerative diseases including cancer, we aim to start moving out of the chemical domain and into the biological one. Some MSNPs are already being tested in biological systems.

Selective Degradation of Organic Pollutants Using an Efficient Metal-free Catalyst Derived from Carbonized Polypyrrole via Peroxymonosulfate Activation

Abstract: Metal-free carbonaceous materials, including nitrogen-doped graphene and carbon nanotubes, are emerging as alternative catalysts for peroxymonosulfate (PMS) activation to avoid drawbacks of conventional transition metal-containing catalysts, such as the leaching of toxic metal ions. However, these novel carbocatalysts face relatively high cost and complex syntheses, and their activation mechanisms have not been well-understood. Herein, we developed a novel nitrogen-doped carbonaceous nanosphere catalyst by carbonization of polypyrrole, which was prepared through a scalable chemical oxidative polymerization. The defective degree of carbon substrate and amount of nitrogen dopants (i.e., graphitic nitrogen) were modulated by the calcination temperature. The product carbonized at 800 °C (CPPy-F-8) exhibited the best catalytic performance for PMS activation, with 97% phenol degradation efficiency in 120 min. The catalytic system was efficient over a wide pH range (2–9), and the reaction of phenol degradation h...

Dual-action smart coatings with a self-healing superhydrophobic surface and anti-corrosion properties

Abstract: This work introduces a new self-healing superhydrophobic coating based on dual actions by the corrosion inhibitor benzotriazole (BTA) and an epoxy-based shape memory polymer (SMP). Damage to the surface morphology (e.g., crushed areas and scratches) and the corresponding superhydrophobicity are shown to be rapidly healed through a simple heat treatment at 60 °C for 20 min. Electrochemical impedance spectroscopy (EIS) and scanning electrochemical microscopy (SECM) were used to study the anti-corrosion performance of the scratched and the healed superhydrophobic coatings immersed in a 3.5 wt% NaCl solution. The results revealed that the anti-corrosion performance of the scratched coatings was improved upon the incorporation of BTA. After the heat treatment, the scratched superhydrophobic coatings exhibited excellent recovery of their anti-corrosion performance, which is attributed to the closure of the scratch by the shape memory effect and to the improved inhibition efficiency of BTA. Furthermore, we found that the pre-existing corrosion product inside the coating scratch could hinder the scratch closure by the shape memory effect and reduce the coating adhesion in the scratched region. However, the addition of BTA effectively suppressed the formation of corrosion products and enhanced the self-healing and adhesion performance under these conditions. Importantly, we also demonstrated that these coatings can be autonomously healed within 1 h in an outdoor environment using sunlight as the heat source.

Scalable synthesis of Ca-doped α-Fe2O3 with abundant oxygen vacancies for enhanced degradation of organic pollutants through peroxymonosulfate activation

Abstract: In this work, a cost-effective and eco-friendly calcium-doped α-Fe2O3 (Ca-Fe2O3) with abundant oxygen vacancies was fabricated using a scalable precipitation-calcination method to activate peroxymonosulfate (PMS) for wastewater purification. Density functional theory calculations revealed that the incorporation of Ca2+ into the α-Fe2O3 structure enhances the electron transfer from α-Fe2O3 to PMS, facilitating the activation of PMS. The degradation of Rhodamine B by 5%Ca-Fe2O3 proceeded with a reaction constant 8 times higher than that of pristine α-Fe2O3. This can be attributed to the increased generation of 1O2 and O2•−, increased specific surface area and enhanced electrical conductivity. The applicability of the 5%Ca-Fe2O3/PMS system was investigated including its operating parameters and stability, and the intermediates involved in the reaction were identified. The 5%Ca-Fe2O3/PMS system exhibited excellent degradation efficiency in natural water samples. This work opens up new perspectives for designing highly efficient catalysts and renders iron oxides potential candidates for environmental remediation.

Supramolecular Antibacterial Materials for Combatting Antibiotic Resistance

Abstract: Antibiotic-resistant bacteria have emerged as a severe threat to human health. As effective antibacterial therapies, supramolecular materials display unprecedented advantages because of the flexible and tunable nature of their noncovalent interactions with biomolecules and the ability to incorporate various active agents in their platforms. Herein, supramolecular antibacterial materials are discussed using a format that focuses on their fundamental active elements and on recent advances including material selection, fabrication methods, structural characterization, and activity performance.