Corrosion product formed on zinc sample during 2 weeks immersion in saline solution has been investigated. The corrosion layer morphology as well as its chemical composition, was analyzed using scanning electron microscopy (SEM), x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). Electrochemical measurement was used to analyze the corrosion behavior. Zinc oxide, zinc hydroxide and zinc hydroxide chloride were formed on zinc surface in saline solution. The thickness of corrosion layer increased with the time increased. The pure Zn has an estimated corrosion rate of 0.063 mm y−1 after immersion for 336 h. Probable mechanisms of zinc corrosion products formation are presented.

A novel type of hydrophobic association hydrogels (HA-gels) was prepared through micellar copolymerization of acrylic acid (AA), acrylamide (AAm) as basic monomers and a small amount of octylphenol polyoxyethylene ether acrylate with seven ethoxyl units (OP7-AC) as hydrophobic association monomer. The HA-gels exhibited desirable mechanical property and stably reversible phase transition between opaque and transparency. The influences of adding urea and varying AA:AAm molar ratio on the phase transition behavior were discussed, which indicated that the phase transition was introduced by forming or dissociating of hydrogen bonding between amide and carboxyl groups. The introduction of hydrophobic units (OP7-AC) to poly(acrylic acid-co-acrylamide) (P(AA-AAm)) copolymer would result in the adulterating and cross-linking effects on the transition temperature. The former sharply reduced the transition temperature while the later gradually raised it. The transition temperature became linearly dropping with the increasing sodium dodecyl sulfate (SDS) content in the HA-gels. Therefore, the phase transition temperature can be finely adjusted by means of changing AA:AAm ratio, concentration, OP7-AC and/or SDS dosages in the synthesis of HA-gels.

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Hydrophobic association hydrogels (HA‐gels) with almost ideal properties were successfully prepared by micellar copolymerization, and the associated micelles acted as physical cross‐linking points in the network of HA‐gels. HA‐gels exhibit exceptional mechanical properties and transparency. However, the most striking properties are that HA‐gels possess the capability of self‐healing and remolding, which is mainly due to the dissociation and re‐association process of the associated micelles. Dried‐gels, which were prepared by stretching HA‐gels to a certain elongation for a period of time in the air, can be used as shrinkable or thermal sensitivity materials. HA‐gels have a broad selectivity for components, so we have synthesized HA‐gels with variously available properties by changing a corresponding component: thermoresponsive HA‐gels, nanosphere‐composite HA‐gels, and fluorescent HA‐gels. Therefore, we are sure that HA‐gels will be widely used in various fields, such as biology, medication, sensors, optics, and oil exploitation.magnified image

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The comprehensive utilization of food-derived nutraceuticals with different polarities has been extremely restricted by their poor bioavailability and coexistence in a single system. This study aimed to fabricate a self-assembly of amphiphilic nanoparticles (NPs) for the hydrophilic EWDP and hydrophobic curcumin based on the carboxymethyl chitosan (CMCS) shell and γ-cyclodextrin (γ-CD) core. Notably, EWDP could cooperate with CMCS to yield superior colloidal properties with an excellent curcumin aqueous solubility and co-encapsulation capacity (>10%) for the NPs (pH 2.0−7.0). This phenomenon was mainly ascribed to the additional hydrogen-bonding network and hydrophobic interaction introduced by EWDP. Besides, the overall antioxidant activity, bioaccessibility, gastrointestinal stability, and Caco-2 cell absorption properties were significantly improved in the presence of EWDP (>20% increase). Therefore, EWDP could function as both a potential affinity agent and a nutrition enhancer to expand the co-delivery applications for diverse nutraceuticals with promising oral bioavailability enhancement in food and pharmaceutical areas.

Zn-passivated carbon dots (named Z-CDs) were synthesized from zinc gluconate for the first time through a one-step pyrolysis treatment. The mechanism of Zn-enhanced fluorescence was carefully investigated, and a new strategy to passivate the surfaces of CDs by Zn was proposed. Inspired by the complexation reaction between Zn and ethylenediaminetetraacetic acid (EDTA), a reversible "off-on" fluorescent nanosensor for the detection of EDTA and Zn was constructed based on the depassivation and repassivation of Z-CDs, with a limit of detection as low as 3.2 × 10 M and 5.1 × 10 M, respectively. The proposed Z-CD-based nanosensor had been further utilized for EDTA and Zn monitoring in tap water with excellent recovery. To the best of our knowledge, this was the first report of a fluorescence-based sensor of EDTA and a turn-on sensor of Zn based on CDs with reversible detection capability. Also, benefiting from the low toxicity of zinc, Z-CDs were applied for multicolor bioimaging and in vitro detection in cells.