Double-Network Polymer Electrolytes with Ionic Liquids for Lithium Metal Batteries.

Solid-state polymer electrolytes have become promising candidates for high-energy-density lithium metal batteries (LMBs). However, they suffer from low ionic conductivities at room temperature. In this work, two types of composite polymer electrolytes based on a double-network polymer, an ionic liquid (IL) of 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl) imide (Pyr14TFSI) or 1-ethyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl) imide (EmimTFSI), and bis(trifluoromethane)sulfonamide lithium salt (LiTFSI) were prepared by a facile one-pot method. The two types of CPEs possess good mechanical properties, excellent thermal stability, and high ionic conductivities greater than 10-4 S cm-1 at 20 °C with 26 wt% IL. The performance diversity of the CPEs was also carefully investigated through a series of electrochemical measurements. Although the CPEs containing EmimTFSI show higher ionic conductivities than those of CPEs with Pyr14TFSI, the latter ones have wider electrochemical stability windows and better resistance to the growth of lithium dendrites. Moreover, CPE with 34 wt% Pyr14TFSI leads to Li/LiFePO4 batteries with favorable rate capability and cycling stability and a columbic efficiency of 98.8% at 20 °C, which suggests that CPEs are promising for practical application in solid-state LMBs.

A hierarchical system of covalent and dual non-covalent crosslinks promotes the toughness and self-healing properties of polymer hydrogels.

While it is challenging to simultaneously achieve both high mechanical performance and self-healing ability within one polymer hydrogel network, we, herein, synthesized a novel class of hydrogels based on a combination of chemical and dual non-covalent crosslinks via micellar polymerization of 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, end-capped by 2-hydroxyethyl methacrylate (IPDI-HEMA), with acrylamide (AM). The prepared hydrogels were demonstrated to possess a tensile elongation at a break of at least 1900%, a fracture energy of 138.4 kJ m-3, and remarkable self-healing behaviors (e.g., a strong self-healing ability achieved at ambient temperature without the need for any stimulus or healing agent). The multiple crosslinks developed in this study for one polymer hydrogel network are significant steps to construct the desired functional hydrogels with excellent self-healing and mechanical properties.

Structure and Oxidation Effects on Conformation and Thermoresponsiveness of the OEGylated Poly(glutamic acid)-Bearing Side-Chain Thioether Linkers.

A series of side-chain thioether-linked OEGylated poly(glutamic acid) (PGAs) have been synthesized by "thiol-ene" synthetic methodology, where both the oligo-ethylene glycol (OEG) length and the hydrophobic linkers at the side chains are varied to learn how these structural features affect the secondary structure and thermoresponsive behaviors in water. Before side-chain oxidation, the structural factors affecting the α-helicity include the backbone length, the OEG length, and the hydrophobic linkers' length at the side chains; however, the OEG length plays the most crucial role among these factors because longer OEG around the peripheral side chains can stop water penetration into the backbone to disturb the intramolecular H bonds, which finally allows stabilizing the α-helix; after the oxidation, the polypeptides show increased α-helicity because of the enhanced hydrophilicity. More interestingly, a rare oxidation-induced conformation transition from the ordered ß-sheet to the ordered α-helix can be achieved. In addition, only the OEGylated poly(glutamic acids) (PGAs) with shorter hydrophobic linkers and longer OEG can display the thermoresponsive properties before the oxidation but the subsequent oxidation can cause the polypeptides bearing longer hydrophobic linkers to exhibit the thermosensitivity since sulfone formation at the side chain can lead to final hydrophilicity-hydrophobicity balance. This work is meaningful to understand the secondary structure-associated solution behaviors of the synthetic polypeptides.

Highly tough and rapid self-healing dual-physical crosslinking poly(DMAA-co-AM) hydrogel.

Introducing double physical crosslinking reagents (i.e., a hydrophobic monomer micelle and the LAPONITE® XLG nano-clay) into the copolymerization reaction of hydrophilic monomers of N,N-dimethylacrylamide (DMAA) and acrylamide (AM) is reported here by a thermally induced free-radical polymerization method, resulting in a highly tough and rapid self-healing dual-physical crosslinking poly(DMAA-co-AM) hydrogel. The mechanical and self-healing properties can be finely tuned by varying the weight ratio of nanoclay to DMAA. The tensile strength and elongation at break of the resulting nanocomposite hydrogel can be modulated in the range of 7.5-60 kPa and 1630-3000%, respectively. Notably, such a tough hydrogel also exhibits fast self-healing properties, e.g., its self-healing rate reaches 48% and 80% within 2 and 24 h, respectively.

Porous Organic Polymers with Thiourea Linkages (POP-TUs): Effective and Recyclable Organocatalysts for the Michael Reaction.

As novel porous organic polymers with thiourea linkages, POP-TUs were successfully synthesized with tris(4-aminophenyl) amine (TAA) and 1,4-phenylene diisothiocyanate (PDT) under different conditions. The as-synthesized POP-TUs possess distinctly different morphological characteristics and can effectively catalyze the Michael reaction of trans-ß-nitrostyrenes to diethyl malonate. Particularly, the POP-TU-2-catalyzed Michael reaction can proceed smoothly even using an ultralow catalyst dosage of 0.03 mol %, whose turnover number (TON) and turnover frequency (TOF) can reach up to 2700 and 25 h-1, respectively. Besides, POP-TU-2 also exhibits excellent recyclability and reusability. Only 2% decline in the isolated yield was found after five consecutive runs. This work shows a significant improvement over previously reported thiourea-based catalysts and can offer an effective strategy for developing highly efficient heterogeneous organocatalysts.

Preparation and Properties of Polydimethylsiloxane (PDMS)/Polyethylene Glycol (PEG)-Based Amphiphilic Polyurethane Elastomers.

Amphiphilic polyurethane elastomers (APUE) were synthesized using a two-step polyaddition reaction based on the hydroxyl-terminated polydimethylsiloxane (PDMS) and polyethylene glycol (PEG) soft segments with the molecular weights (Mw's) of 2000 and 1000, respectively. The effects of the PDMS/PEG contents on the properties and structures of the APUE were investigated. It was found that the APUE possessed high elongation, moderate tensile strength, and good thermal properties. In addition, the APUE showed tunable oxygen permeability (Dk) and water vapor transmission rate (WVTR), and a similar WVTR to that of skin could be obtained for the optimized sample (APUE2). Importantly, APUE also exhibited excellent antibacterial efficacy against two kinds of bacteria along with impressive cytocompatibility. All of the results demonstrated that the synthesized APUE will hold substantial potential for biomaterial applications.

Self-healing zwitterionic sulfobetaine nanocomposite hydrogels with good mechanical properties.

The development of zwitterionic hydrogels possessing both excellent self-healing and mechanical properties is of great significance. Herein, a class of zwitterionic sulfobetaine nanocomposite hydrogels was prepared by UV-initiated copolymerisation of zwitterionic sulfobetaine monomer N,N-dimethyl-N-(3-methacrylamidopropyl)-N-(3-sulfopropyl) ammonium betaine (DMAPMAPS) and 2-hydroxyethyl methacrylate (HEMA) in the presence of exfoliated clay platelets uniformly dispersed in an aqueous medium. The effects of the hydrogel compositions, including the DMAPMAPS/HEMA mass ratio and the amount of clay, on the self-healing behaviors and mechanical properties of the nanocomposite hydrogels were investigated. The results indicate that the fabricated zwitterionic sulfobetaine nanocomposite hydrogels can autonomously repair incisions or cracks at ambient temperature without the need for any stimulus and possess excellent mechanical properties.

Preparation and characterization of protein-resistant hydrogels for soft contact lens applications via radical copolymerization involving a zwitterionic sulfobetaine comonomer.

We aimed to introduce hydrophilic sulfobetaine-type zwitterionic groups to macromolecular chains of copolymers to construct novel copolymer hydrogels with anti-protein-fouling performance that could be used as soft contact lens (SCL) materials. Using hydroxyethyl methacrylate (HEMA), N-vinyl pyrrolidinone (NVP) and sulfobetaine methacrylate (SBMA) as comonomers, several copolymer hydrogels with different SBMA contents, poly(HEMA-NVP-SBMA), are synthesized via radical copolymerization in an aqueous phase. Surface chemistry, structural morphologies, water contact angle (WCA), equilibrium water content (EWC), visible light transmittance and tensile mechanical properties are investigated. The prepared hydrogels exhibit a closed-type porous structure. With increasing SBMA content in the comonomer mixture, the prepared copolymer hydrogel pore size gradually increases up to the micron level, WCA tends to decrease, EWC tends to increase, and visible light transmittance slightly increases, but their tensile mechanical properties decline. The amounts of protein Lyz and BSA adsorbed on the copolymer hydrogels and on commercially available EASY DAY® SCLs as a control are also determined by protein adsorption tests. The amount of protein adsorbed on the copolymer hydrogel decreases with increasing SBMA content. For the hydrogel prepared using the comonomer mixture with 5.0 wt % SBMA, the amount of adsorbed Lyz is 0.91 µg/cm2, which corresponds to only 56.8% of the amount adsorbed on EASY DAY® SCLs. Thus, novel SCL materials with high water content and excellent anti-protein-fouling performance were efficiently constructed by introducing sulfobetaine-type zwitterionic groups into a traditional polymer hydrogel system.

Improved Performance by SiO2 Hollow Nanospheres for Silver Nanowire-Based Flexible Transparent Conductive Films.

Flexible transparent conductive films (TCFs) have attracted tremendous interest thanks to the rapid development of portable/flexible/wearable electronics. TCFs on the basis of silver nanowires (AgNWs) with excellent performance are becoming an efficient alternative to replace the brittle transparent metal oxide. In this study, a promising method was developed by introducing SiO2 hollow nanospheres (SiO2-HNSs) into the film to significantly improve the performance of AgNW-based TCFs. Since SiO2-HNSs have opposite charges to AgNWs, the strong attraction had promoted a uniform distribution of AgNWs and made the distance between AgNWs closer, which could decrease the contact resistance greatly. The introduction of SiO2 layer remarkably enhanced the transmission of visible light and the conductivity. In addition, the TCFs constructed by AgNWs and SiO2-HNSs showed much higher thermal stability and adhesive force than those by only AgNWs. As an example, the transmission of AgNW/SiO2-HNS-coated poly(ethylene terephthalate) (PET) could increase about 14.3% in comparison to AgNW-coated PET. Typically, a AgNW/SiO2-HNS-based TCF with a sheet resistance of about 33 Ω/sq and transmittance of about 98.0% (excluding substrate) could be obtained with excellent flexibility, adhesion, and thermal stability. At last some devices were fabricated.

Preparation, anti-biofouling and drag-reduction properties of a biomimetic shark skin surface.

Shark skin surfaces show non-smoothness characteristics due to the presence of a riblet structure. In this study, biomimetic shark skin was prepared by using the polydimethylsiloxane (PDMS)-embedded elastomeric stamping (PEES) method. Scanning electron microscopy (SEM) was used to examine the surface microstructure and fine structure of shark skin and biomimetic shark skin. To analyse the hydrophobic mechanism of the shark skin surface microstructure, the effect of biomimetic shark skin surface microstructure on surface wettability was evaluated by recording water contact angle. Additionally, protein adhesion experiments and anti-algae adhesion performance testing experiments were used to investigate and evaluate the anti-biofouling properties of the surface microstructure of biomimetic shark skin. The recorded values of the water contact angle of differently microstructured surfaces revealed that specific microstructures have certain effects on surface wettability. The anti-biofouling properties of the biomimetic shark skin surface with microstructures were superior to a smooth surface using the same polymers as substrates. Moreover, the air layer fixed on the surface of the biomimetic shark skin was found to play a key role in their antibiont adhesion property. An experiment into drag reduction was also conducted. Based on the experimental results, the microstructured surface of the prepared biomimetic shark skin played a significant role in reducing drag. The maximum of drag reduction rate is 12.5%, which is higher than the corresponding maximum drag reduction rate of membrane material with a smooth surface.

[Discovery of topiramate's new functions based on medicinal property combinations and study on its mechanism].

OBJECTIVE: To study topiramate's new functions according to the medicinal property combinations, in order to apply the traditional Chinese medicinal theory in discovering new purposes of old drugs. METHOD: According to New Traditional Chinese Medicinal Families--Chemical Traditional Chinese Medicines, the authors found out topiramate's property. Then based on the therapeutic principle of diabetes, hypertension, epilepsy and lung cancer, as well as the relations of efficacies and medicinal property combinations, they summarized the corresponding medicinal property combination modes, compared topiramate's medicinal property combination mode with corresponding medicinal property combination modes of these diseases, and predict topiramate's new functions. RESULT: According to the comparison, the corresponding medicinal property combinations were consistent with topiramate's medicinal property combinations as evidenced by corresponding literatures, whereas other medicinal property combinations were not. CONCLUSION: Based on medicinal property combination modes, the authors screened topiramate's new functions according to e of TCM clinical experience, discovered topiramate's therapeutic effects on diabetes, hypertension and lung cancer in addition to epilepsy, and explore new drug function according to medicinal property combination modes, which could help greatly shorten the new drug R&D period.

An intermolecular quadruple hydrogen-bonding strategy to fabricate self-healing and highly deformable polyurethane hydrogels.

The development of hydrogels possessing both excellent self-healing and mechanical properties in hydrogel science due to their tight relationship with the many potential application scopes is of great significance. Herein, a novel class of polyurethane (PU) hydrogels with intermolecular quadruple hydrogen-bonding interactions were designed and fabricated by the copolymerization of poly(ethylene glycol) methacrylate end-capped urethane ether prepolymer (PU-PEGMA) with 2-(3-(6-methyl-4-oxo-1,4-dihydropyrimidin-2-yl)ureido)ethyl methacrylate (SCMHBMA) bearing the 2-ureido-4-pyrimidone (UPy) unit. The effects of the SCMHBMA content on the self-healing behaviors and mechanical properties of the PU hydrogels were investigated. The results indicate that the fabricated PU hydrogels can autonomously and rapidly repair occurring incisions or cracks at ambient temperature without the need for any stimulus and possess high deformability under both tensile and compressive stress and strong recoverability upon removal of stress, thus exhibiting outstanding self-healing, elasticity, robustness and toughness. The presence of UPy units in PU macromolecular chains is a decisive factor endowing the PU hydrogels with these characteristics.

A new method for producing "Lotus Effect" on a biomimetic shark skin.

Nature has long been an important source of inspiration for mankind to develop artificial ways to mimic the remarkable properties of biological systems. In this work, a new method was explored to fabricate a superhydrophobic dual-biomimetic surface comprising both the shark-skin surface morphology and the lotus leaf-like hierarchical micro/nano-structures. The biomimetic surface possessing shark-skin pattern microstructure was first fabricated by microreplication of shark-skin surface based on PDMS; and then it was treated by flame to form hierarchical micro/nano-structures that can produce lotus effect. The fabricated biomimetic surfaces were characterized with scanning electron microscopy (SEM), water contact angle measurements and liquid drop impact experiments. The results show that the fabricated dual-biomimetic surface possesses both the vivid shark-skin surface morphology and the lotus leaf-like hierarchical micro/nano-structures. It can exhibit excellent superhydrophobicity that the contact angle is as high as 160° and maintain its robustness of the superhydrophobicity during the droplet impact process at a relatively high Weber number. The mechanism of the micromorphology evolution and microstructural changes on the biomimetic shark-skin surface was also discussed here in the process of flame treatment. This method is expected to be developed into a novel and feasible biomimetic surface manufacturing technique.

Click chemistry: a route to designing and preparing pseudo-biospecific immunoadsorbent for IgG adsorption.

L-histidine is a promising alternative to expensive protein ligands for the adsorption of IgG due to its high selectivity, no toxicity and low cost; while click chemistry can improve the reaction selectivity between the ligands and the support matrix under mild reaction conditions. Thus, using L-histidine as a ligand and original sepharose gel as a support, a novel immunoadsorbent possessing pseudo-biospecific affinity for IgG from human plasma, Sep-triazole-His, was designed and prepared according to the principle of Click-reaction between alkyne and azide functional groups; while both sepharose-based control samples Sep-His and Sep-PA were prepared by a conventional method using L-histidine and protein A as a ligand, respectively. The ligand density and IgG adsorption performance of Sep-triazole-His from human plasma were measured and evaluated. The influences of click chemistry on the preparation, structure and performance of sepharose-based immunoadsorbent were also investigated. The results indicate that the ligand density immobilized on Sep-triazole-His is 319.1 µmol/g sepharose gel, almost 4-fold as high as that on Sep-His; the IgG adsorption capacity of Sep-triazole-His from human plasma reaches 16.49 mg/g at pH 7.0, or increases 5.72-fold with respect to Sep-His, and does not decrease noticeably after being repeatedly used for 10 times; and Sep-triazole-His can exhibit high adsorption selectivity for IgG comparable to Sep-PA. The further studies prove that the 1,2,3-triazole ring in the spacer-arm of Sep-triazole-His, can facilitate the binding of IgG without non-specific adsorption.