Showing papers by "Ming Qiu Zhang published in 2016"
TL;DR: In this article, a crosslinked polyurethane carrying disulfide in the main chain is synthesized for realizing sunlight stimulated self-healing, and the macromolecular composition and architecture are optimized so that the included disulide bonds can take part in the exchange reaction simply under illumination of the low concentration UV component of sunlight.
Abstract: For realizing sunlight stimulated self-healing, a crosslinked polyurethane carrying disulfide in the main chain is synthesized. Its macromolecular composition and architecture are optimized so that the included disulfide bonds can take part in the exchange reaction simply under illumination of the low concentration UV component of sunlight. Accordingly, the damaged polymer is allowed to be repeatedly healed in the sun in terms of strength restoration as a result of photo-triggered reversible exchange of disulfide bonds. Meanwhile, the elaborately introduced hydrogen bonding helps to quickly close cracks, favoring intimate contacts of the cracked surface and subsequent interaction of dangling chains across the interface, and eventually raising the effectiveness of the photo-reaction of the disulfide bonds in the solid phase. In addition, network rearrangement due to disulfide exchange enables multiple recycling and reshaping of the polymer under sunshine. The present proof-of-concept work would be hopefully developed into a cost-effective and environmentally friendly technology of design, fabrication and application of smart photo-sensitive polymers with high mechanical strength.
163 citations
TL;DR: In this article, a new technology for sustainable application of sulfur crosslinked rubbers, a novel latent catalyst, organic complex copper(II) methacrylate (MA-Cu), is explored to trigger disulfide metathesis at elevated temperature.
Abstract: To develop a new technology for sustainable application of sulfur cross-linked rubbers, a novel latent catalyst, organic complex copper(II) methacrylate (MA-Cu), is explored to trigger disulfide metathesis at elevated temperature. When it is incorporated into vulcanized chloroprene rubber fabricated following industrial recipe, reshuffling of inherent sulfur cross-links is enabled typically at 120 °C, while microstructure of the material remains unchanged at lower temperature (typically lower than 100 °C). Such a latent character of MA-Cu is believed to ensure operation stability of the rubber under ambient conditions, and its organic nature helps to improve dispersion homogeneity. By taking advantage of the activated cross-linked networks, the sulfur bonds can be reversibly exchanged inside the vulcanized chloroprene rubber as well as across the surfaces at 120 °C. As a result, the rubber is coupled with the capabilities of repeated reshaping, self-healing, and recycling without need of changing its macr...
95 citations
TL;DR: Bulk polymer capable of repeatedly underwater self-healing and reclaiming is synthesized under the inspiration of the formation of a mussel byssus cuticle.
Abstract: In this work, water triggered dynamic catechol–Fe3+ coordinate bonds are revealed and studied at atomic, molecular and macroscopic levels using Mossbauer spectroscopy, rheological analysis, etc. DOPA–iron complexation is found to be dynamic in the presence of water, and this dynamic manner is immobilized after removing water. Accordingly, a water saturated lipophilic polymer containing catechol–Fe3+ crosslinks, rather than the dry version, exhibits dynamic coordination–dissociation behavior. In addition, a migration of iron proves to be enabled in the catechol–Fe3+ crosslinked polymer immersed in seawater. Rearrangement of the dynamic catechol–Fe3+ coordinate bonds among different molecules is thus favored. Based on these results, we develop a bulk lipophilic polymer solid capable of repeated autonomic recovery of strength in seawater without manual intervention. When the polymer is damaged in seawater, reshuffling of the mobile hyperbranched polymer networks across the crack interface, owing to the dynamic catechol–Fe3+ crosslinkages activated by the alkaline circumstances, rebinds the damaged site. By taking advantage of the same mechanism, the polymer can be remolded with the help of seawater and this recycled polymer is still self-healable in seawater. Unlike in the case of conventional polymers where water would shield macromolecules from interacting, here, seawater is a necessary environmental assistant for the material interaction to take effect. The outcomes are beneficial for deepening the understanding of coordinate bonds, and the development of robust underwater self-healing lipophilic polymers.
89 citations
TL;DR: In this article, the authors used carbon dots with amino groups as an efficient interfacial modification layer on the ZnO or AZO interlayers, greatly improving the device performance.
79 citations
TL;DR: In this paper, hyperbranched polyurethane containing a few hydrophilic quaternary ammonium salts and abundant dynamic reversible catechol-B3+ crosslinkages is synthesized as the first step in this direction.
Abstract: To develop a lipophilic bulk polymer capable of self-healing and recycling for future structural applications in different aquatic environments, hyperbranched polyurethane containing a few hydrophilic quaternary ammonium salts and abundant dynamic reversible catechol–B3+ crosslinkages is synthesized as our first step in this direction. The compositional and structural design ensures dynamicity of the polymer networks as well as effective interdiffusion and interaction of dangling chains on the damaged surface in water. More importantly, the boronic ester bonds become not easily hydrolyzed at lower pH due to the electron attracting effect of quaternary ammonium cations from catechol–B3+ bonds. Qualitative visual inspection and quantitative tensile tests demonstrate that the proposed idea works, and the target polymer is allowed to be self-healed and reprocessed in waters at pH 7 and 9 at room temperature. Reshuffling and rearrangement of the polymer networks via dynamic reversible coordination of catechol–B3+ bonds helps to re-bond the interface. The technical route provides an effective solution to stabilizing catechol–B3+ bonds at lower pH, and obviously reduces the pH sensitivity of boronic ester bonds, which is the objective of the current work. As a result, the adaptivity and serviceable range of the underwater intrinsic self-healing polymer are expanded.
67 citations
TL;DR: The origin of the PL behavior and PL quenching mechanism was explored in terms of the interaction between the functional groups on the surfaces of GOQDs or PQDs and Hg(2+).
Abstract: A simple, effective and green bottom-up method for the synthesis of highly fluorescent N doped graphene oxide quantum dots (GOQDs) and polymer-like quantum dots (PQDs) was developed on the basis of rapid one-step microwave assisted pyrolysis of citric acid (CA) and diethylenetriamine (DETA) in different reaction solvents. Both one-photon-induced and two-photon-induced photoluminescence (PL) properties of the resultant GOQDs and PQDs were characterized and analyzed. The one-photon-induced PL quantum yields (QY) of GOQDs and PQDs reached 39.8 and 74.0%, respectively, which are high enough to exhibit strong photoluminescence (PL) emission even under daylight excitation. The origin of the PL behavior and PL quenching mechanism was explored in terms of the interaction between the functional groups on the surfaces of GOQDs or PQDs and Hg(2+). Furthermore, due to the excellent selectivity and sensitivity of the GOQDs and PQDs to Hg(2+), the quantum dots might be used for quantitative detection of Hg(2+) in aqueous solution.
50 citations
TL;DR: In this article, a self-healing glass fiber/epoxy composite, in which plastic (polypropylene (PP)) tubes were embedded and used as containers of epoxy/mercaptan healing agent and foaming agent, was presented.
43 citations
TL;DR: Mechanistic studies indicated that the ubiquitous galvanic corrosion combined with decomposition of adsorbed trace water in the semi-conducting polymer foam enabled the generation of electricity, which overturns the traditional view.
Abstract: The present communication reports a concept battery made by direct contact of magnesium foil with ultralight polyaniline (PANI) foam in the absence of additional electrolyte. Electrical current is allowed to be steadily released from the junction with a specific energy of 646 mWh g(-1) and specific capacity of 1247 mAh g(-1). Additionally, the battery offers an environmentally friendly route of hydrogen production along with discharging. Mechanistic studies indicated that the ubiquitous galvanic corrosion combined with decomposition of adsorbed trace water in the semi-conducting polymer foam enabled the generation of electricity, which overturns the traditional view. The higher moisture level is conducive to the discharge. This work is believed to open up new possibilities for the design of electrochemical batteries.
36 citations
TL;DR: In this paper, a crosslinked methyl methacrylate polymer with embedded alkoxyamine moieties that contain amido groups is prepared to improve the room temperature application stability of a dynamically reversible self-healing system.
Abstract: To improve the room temperature application stability of a dynamically reversible self-healing system based on alkoxyamine moieties, and to provide the polymer with oxygen insensitive self-healability, a crosslinked methyl methacrylate polymer with embedded alkoxyamine moieties that contain amido groups is prepared. Owing to synchronous fission/radical recombination of C–ON bonds, cracks in the polymer can be repeatedly healed without an additional catalyst, and the polymer itself can be remolded in the solid state or even decomposed by nitroxides in a controlled manner. The homolysis temperature of the dynamic reversible alkoxyamine derivative, which is closely related to crack healing and the reprocessing temperature of the polymer, is adjusted to be higher than room temperature by means of the appropriate electron-absorbing feature of amido groups. Meanwhile, the healing chemistry is coupled with air resistance. Besides, thiol–ene click chemistry is used to synthesize the target polymer. The possible side reaction that reduces the concentration of reversible bonds during polymerization is minimized accordingly.
30 citations
TL;DR: The pioneered construction of novel monodisperse hollow and yolk-shell structured periodic mesoporous polymer nanoparticles was reported by the development of an efficient reactive interface-guided co-assembly approach.
28 citations
TL;DR: The interconnected ordered pore channels facilitate faster permeation of Li(+) ions during the charge-discharge process than the isolated ordered p pores, resulting in significantly enhanced capacities, better rate capabilities and more remarkable cycling stability.
TL;DR: In this paper, a new polymer nanocomposite of nano-titanium dioxide/polyethylene oxide (TiO2/PEO) incorporated with in situ synthesized hyperbranched poly(amine-ester) (HBPAE) and its application as a polymer electrolyte was reported.
Abstract: This paper has reported a new polymer nanocomposite of nano-titanium dioxide/polyethylene oxide (TiO2/PEO) incorporated with in situ synthesized hyper-branched poly(amine-ester) (HBPAE) and its application as a polymer electrolyte. Firstly, the HBPAE/HBPAE-g-TiO2/PEO is obtained by synthesizing HBPAE in methyl acrylic acid methyl ester grafted TiO2 (MMA-g-TiO2)/PEO, to simultaneously form the hypergrafted polymer on the nano inclusions (HBPAE-g-TiO2) and hyperbranched particles dispersed in the PEO. Then the Li2SO4 is introduced to prepare the polymer electrolyte, and the relevant structure and properties are studied. It is found that the incorporation of HBPAE into TiO2/PEO can benefit the ionic transportation of the composite electrolyte, and can bridge the nano inclusions which further improves ionic conductivity. The best ionic conductivity of the HBPAE/HBPAE-g-TiO2/PEO polymer electrolyte with 15 wt% TiO2 content can reach as high as 3.2 mS cm−1, which is ∼10 times of that of the PEO electrolyte and ∼28% of that of the HBPAE-g-TiO2/PEO electrolyte without homopolymer component. Furthermore, the optimized polymer electrolyte is assembled into a LiTi2(PO4)3//LiMn2O4 lithium-ion battery, with better excellent cell performance compared with the PEO electrolyte. This study shows that the new polymer nanocomposite has great potential for the assembly of high performance solid electrochemical devices.
TL;DR: In this article, molecular chain bonding is used to synthesize a nanoporous, flexible and conductive polymer composite by converting a single polymer phase matrix to two phases of interpenetrating polymer networks.
Abstract: Molecular chain bonding is, for the first time, developed to synthesize a nanoporous, flexible and conductive polymer composite by converting a single polymer phase matrix to two phases of interpenetrating polymer networks. Significantly, the porous polymer composite not only presents ultra-high mechanical properties, durability and conductive stability, but also enhances the capacitance by 7-fold.
TL;DR: In this paper, a supercapacitor with the addition of poly(amine-ester) nano-silica (HBPAE-SiO2) was evaluated by cyclic voltammetry, galvanostatic charge-discharge behavior, and electrochemical impedance spectroscopy.
Abstract: In the developing of wearable electronics and smart textiles, thin, lightweight, and flexible energy storage supercapacitor with high energy density has attracted the attention of many researchers in recent years. In this work, we prepared gel nano-composite electrolyte with the hypergrafted poly (amine-ester) nano-silica (HBPAE-SiO2) as inclusion. The electrochemical properties of the supercapacitor with the alkaline polymer electrolyte were evaluated by cyclic voltammetry, galvanostatic charge–discharge behavior, and electrochemical impedance spectroscopy. It was found that the incorporated HBPAE-SiO2 can greatly increase the specific capacitance of the supercapacitor, which was due to the enhanced ionic conductivity of gel electrolyte as well as good electrode–electrolyte contact. It is pointed out that the electroactivity of the inclusion may be also one reason. The best specific capacitance with 30 wt% HBPAE-SiO2 reached 160 F g−1, which was increased by 36.5 % compared with that of polyvinyl alcohol (PVA)-KOH system. Moreover, the capacity retention of solid-state supercapacitor can be 88 % after 10,000 cycles. The hypergrafted nano-silica modified polymer gel electrolyte is promising for the application of solid-state supercapacitor.
TL;DR: In this article, the failure process of self-healing microcapsule filled epoxy composites was investigated with Acoustic Emission (AE) measurement during tapered double cantilever beam (TDCB) tests.
TL;DR: In this paper, a tensile stress relaxation test of a polyurethane crosslinked by catechol-iron coordination bonds was conducted and it was found that the stress gradually increases with time after the initial drop, which differs from the documented behaviors of other materials.
Abstract: The authors report that during tensile stress relaxation test of a polyurethane crosslinked by catechol-iron coordination bonds, the stress gradually increases with time after the initial drop, which differs from the documented behaviors of other materials. Based on model experiment and structural characterization, water triggered rapid increase of dynamic crosslinkages accompanied by Poisson's contraction is found to be responsible for the stress intensification effect. In addition, the influential factors are carefully discussed. The findings might help to develop novel polymeric materials with improved application performance under loading conditions.
TL;DR: In this article, a new solid-state polymer composite electrolyte based on hypergrafted nano-silica (SiO2-g-HBPAE)/hyperbranched poly (amine-ester) doped with lithium perchlorate (LiClO4) was studied.
Abstract: A new solid-state polymer composite electrolyte based on hypergrafted nano-silica (SiO2-g-HBPAE)/hyperbranched poly (amine-ester) (HBPAE) doped with lithium perchlorate (LiClO4) was studied in this paper. The N,N-diethylol-3-amine-2-methyl methylpropionate monomer was firstly synthesized by methyl methacrylate (MMA) and diethanolamine through Michael addition reaction and then self-condensed on the surface of nano-silica pretreated by 3-aminopropyltriethoxysilane (APTES) and MMA. The synthetic procedure of the monomers and SiO2-g-HBPAE/HBPAE was traced by fluorescence spectra. The size and grafting ratio of SiO2-g-HBPAE were characterized by transmission electron microscopy, static light scattering and thermogravimetric analysis. Incorporating SiO2-g-HBPAE to HBPAE could not only decrease the glass transition temperature of polymer according to the differential scanning calorimetry characterization, but also increase the elastic and viscosity modules indicated by rheological measurement results. Electrochemical properties of SiO2-g-HBPAE/HBPAE/LiClO4 were also investigated. The conductivity of SiO2-g-HBPAE/HBPAE with 50 wt% LiClO4 reached 1.4 × 10−5 S/cm at 30 °C and 10−3 S/cm at 100 °C. The lithium-ion transference number of synthesized hyperbranched electrolyte can be up to 0.55.
TL;DR: To avoid the high corrosiveness of the fast-healing epoxy system previously developed by our lab, which contains a strong Lewis acid or Bronsted acid, this article introduced a much less corrosive BF3-amine complex (50% boron trifluoride-2,4-dimethylaniline in 1,4butanediol) as a replacement.
Abstract: To avoid the high corrosiveness of the fast-healing epoxy system previously developed by our lab, which contains a strong Lewis acid or Bronsted acid, we introduced a much less corrosive BF3–amine complex (50% boron trifluoride–2,4-dimethylaniline in 1,4-butanediol) as a replacement. The new hardener was successfully synthesized, encapsulated in silica hollow microcapsules, and embedded in an epoxy matrix with a microencapsulated cycloaliphatic epoxy monomer. Impact tests indicated that the healing system worked as expected. The self-healing epoxy composite can regain its strength within seconds at room temperature, and its self-healability remained stable after 4 months of storage. The high cationic polymerization reactivity of the cycloaliphatic epoxy accounts for the rapid restoration. It is believed that the present work represents an important step towards practical usage of the fast extrinsic self-healing strategy.
09 Mar 2016
TL;DR: In this article, a self-healing polymeric adhesive formulation with epoxy/mercaptan microcapsules was developed for bonding 5000 series aluminum alloys after mechanical and alkaline cleaning surface treatment.
Abstract: The aim of this work is to develop a self-healing polymeric adhesive formulation with epoxy/mercaptan microcapsules. Epoxy/mercaptan microcapsules were dispersed into a commercialize two-part epoxy adhesive for developing self-healing epoxy adhesive. The influence of different content of microcapsules on the shear strength and healing capability of epoxy adhesive were investigated using single-lap-joints with average thickness of adhesive layer of about 180 µm. This self-healing adhesive was used in bonding of 5000 series aluminum alloys adherents after mechanical and alkaline cleaning surface treatment. The adhesion strength was measured and presented as function of microcapsules loading. The results indicated that the virgin lap shear strength was increased by about 26% with addition of 3 wt% of self-healing microcapsules. 12% to 28% recovery of the shear strength is achieved after self-healing depending on the microcapsules content. Scanning electron microscopy was used to study fracture surface of the...
TL;DR: In this paper, a self-healing system with high heat resistance to tolerate the processing of thermoplastics is developed, where a group of new healants based on atom transfer radical polymerization is developed.
Abstract: Herein, to prepare an extrinsic self-healing system with high heat resistance to tolerate the processing of thermoplastics, a group of new healants based on atom transfer radical polymerization is developed. It consists of microencapsulated acrylate monomers (2-methyl-2-adamantylmethacrylate or trimethylolpropane trimethacrylate), macroinitiator poly(methyl methacrylate)–Br, and supported catalyst (coordination compound of cyclic 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane and cuprous bromide). Composites containing the healing agent with polystyrene, poly(methyl methacrylate) and acrylonitrile-butadiene-styrene copolymer as matrices were successfully manufactured by compression molding. Impact tests indicate that the composites can regain their mechanical strength as a result of polymerization of the released acrylate monomers at room temperature. The strong interaction between the cyclic ligand and CuBr obviously enhances the thermostability of the ligand and depresses the negative influence of cupric ions on the aging properties of the matrix polymers. The present work offers a new route for the design and application of self-healing thermoplastics.
TL;DR: The authors greatly appreciate Tomba's valuable comments on their paper appearing in Soft Matter, and respond to his responses to provide additional information for academic discussion.
Abstract: We greatly appreciate Tomba's valuable comments on our paper appearing in Soft Matter (2012, 8, 4780). Our responses are listed below to provide additional information for academic discussion.