Self-passivation/self-delivery/self-healing anticorrosion polymer coating for marine applications.

Corrosion of steel in the marine environment greatly reduces their service life. Polymeric coatings are the most popular anticorrosion technology, but seawater penetration cannot be prohibited because of the distinct stacking structure of the macromolecular chains. In this context, a novel anticorrosive hyperbranched polyurethane-based coating with dopamine (DOPA) at the terminals is prepared herein. The built-in DOPA is able to capture the iron ions released from the corroded substrate and form DOPA-Fe3+ complexation, which further cooperates with the surrounding seawater and imparts self-passivation, self-delivery and self-healing capabilities to the coating. Under the joint action of these measures, the corrosion of tinplate (serving as the steel model) is reduced to a record-low level (corrosion current = 1 × 10-9 A cm-2, corrosion rate = 1 × 10-5 mm year-1). Conceptually, the present dynamic active anticorrosion strategy greatly outperforms the traditional static passive approach, and turns the unfavorable but unavoidable seawater into a favorable factor, which paves the way for the development of long-lasting marine coatings.

Starch-based self-assembled three-dimensional network nanostructure materials for sustainable cascade adsorption.

Toward the development of a sustainable utilization strategy for adsorption materials, a starch-based adsorbent starch-chitosan-tannic acid (St-CTS-TA) with a three-dimensional (3D) structure was fabricated in water via electrostatic and hydrogen bonding reactions between St, CTS, and TA without using toxic reducing agents or special instruments. St-CTS-TA demonstrated a high specific surface area of 37 m2/g as well as a mesoporous/macroporous distribution ranging from 30 to 80 nm, which enhanced the mass transfer of adsorbate and the exposure of catechol groups in TA. The Langmuir isotherm adsorption model revealed that the highest adsorption capacities of St-CTS-TA for Fe3+ and Co2+ were 1678.2 and 944.8 mg/g, respectively. Surprisingly, the specific surface area of St-CTS-TA increased from 37 to 87 and 42 m2/g after Fe3+ and Co2+ adsorption, respectively, and the resulting St-CTS-TA-Fe and St-CTS-TA-Co could continuously adsorb basic fuchsin (BF) and rhodamine B (RhB). The adsorption capacities of St-CTS-TA-Fe and St-CTS-TA-Co for BF/RhB were found to be 1854.79/401.19 mg/g and 2229.77/537.49 mg/g, respectively, based on the Langmuir isotherm adsorption model.

A functionalized bio-based material with abundant mesopores and catechol groups for efficient removal of boron.

Pursuing a low-cost yet sustainable material with a high performance of removing boron is necessary for replacement of the synthetic adsorbents, but remains challengeable. Herein, we fabricated an mesopore-dominated bio-based material (LS-CPAM-TA) with abundant catechol groups by the electrostatic-interaction-driven self-assembly of lignosulfonate (LS), tannic acid (TA) and cationic polyacrylamide (CPAM) for efficient removal of boron. LS-CPAM-TA presented a mesopore area of 53.9 m2/g with a mesoporous distribution of 2-25 nm, as well as a mesopore/micropore volume ratio of 129.7. Such a mesopore-rich feature not only promoted the exposure of catechol groups in TA, which served as the adsorption sites, but also contributed to enhance the fast mass transport of boron. Consequently, a maximum adsorption capacity of 119.05 mg/g was observed for LS-CPAM-TA, surpassing some reported adsorbents. Even for the low concentration boron, LS-CPAM-TA also displayd the high adsorption efficiency. Moreover, LS-CPAM-TA followed the Langmuir isotherm adsorption model, and presented the excellent regeneration performance due to its robust self-assembled structure driven by the electrostatic interaction among LS, CPAM and TA. This work would provide guidelines for target design of bio-based materials with tunable porous structure and versatile adsorption or catalytic sites for various applications.

Knockdown of enhancer of rudimentary homolog inhibits proliferation and metastasis in ovarian cancer by regulating epithelial-mesenchymal transition.

Ovarian cancer (OC) is the deadliest gynecological malignancy. The pathogenesis of molecular in epithelial ovarian cancer (EOC), main histological type of OC, has not been completely defined. Enhancer of rudimentary homolog (ERH) had been reported to participate in transcriptional regulation, mRNA splicing, DNA repair and DNA synthesis by binding a variety of proteins. In this study, immunohistochemical staining revealed that the protein expression of ERH was associated with histological type, lymph node metastasis and pathological grade in EOC patients. To verify the association of ERH with the prognosis of OC, a GSE microarray dataset was downloaded from the Gene Expression Omnibus (GEO) database. Survival analysis suggested that ERH may be associated with poor prognosis of OC. In addition, shRNA was used to knockdown the protein and mRNA expression levels of ERH in the OC cell line SKOV3. Inhibition of ERH expression slowed proliferation, promoted apoptosis and inhibited metastasis and invasion by regulating epithelial-mesenchymal transition (EMT) in SKOV3 cells. These results indicate that ERH protein promotes the development of OC and provides an experimental basis for ERH as the potential target for ovarian cancer treatment.

Self-Healing of Polymer in Acidic Water toward Strength Restoration through the Synergistic Effect of Hydrophilic and Hydrophobic Interactions.

To improve reliability, durability, and reworkability of bulk polymers utilized in ubiquitous acidic water, the authors develop a novel hyperbranched polymer capable of self-healing and recycling in a low-pH aqueous environment. The hyperbranched polymer has many hydrophilic and hydrophobic terminal groups. When it is damaged in acidic water, the hydrophilic groups are protonated, forming hydrogen bonds, and closing the crack. Meanwhile, hydrophobic interactions of hydrophobic groups are gradually established across the interface because of the intimate contact of the cracked surface, further reinforcing the rebonded portion. The amphiphilic structure proves to meet both the thermodynamic and kinetic requirements for autonomous rehabilitation. As a result, the unfavored water, which used to impede adhesion between hydrophobic polymeric materials, turns into a positive aid to crack healing. The mechanism involved is carefully analyzed and verified in terms of micro- and macroscopic techniques. The proposed operating environment-oriented design of the stimulus-responsive macromolecule may help to broaden the family of underwater self-healing polymers and their application scope.

A seawater triggered dynamic coordinate bond and its application for underwater self-healing and reclaiming of lipophilic polymer.

In this work, water triggered dynamic catechol-Fe3+ coordinate bonds are revealed and studied at atomic, molecular and macroscopic levels using Mössbauer 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.