Tong Liu,Haichao Zhao,Jingyu Li,Dawei Zhang,Wenru Zheng,Liping Wang
A giant molecule containing hydrophobic polyhedral oligomeric silsesquioxane (POSS) and protonic acid-doped tetraaniline (ATA) was designed and synthesized via isocyanate–amine reactions. This flower-like filler exhibits redox activity and high specific capacitance (280 F g −1 ), making it feasible for corrosion protective applications. Electrochemical impedance spectroscopy, local electrochemical impedance spectroscopy, and salt spray tests were performed to evaluate the effect of POSS–ATA on the corrosion inhibition performance of the coating. This giant molecule expands the scope of conducting polymers for the active corrosion inhibition of metallic substrates and provides a platform for studying the multi-responsive self-assembly behaviour of conducting polymers.
In this study, a novel strategy was designed to prepare rapidly recoverable, anti-fatigue, super-tough double-network hydrogels by introducing macromolecular microspheres (MMs) as cross-linking centers for hydrophobic associations. MMs were prepared via emulsion polymerization using butyl acrylate (BA) as a main component and dicyclopentyl acrylate (DCPA) as a cross-linker. Then, a double-network (DN) hydrogel was prepared using gelatin as the first network and a copolymer of acrylamide and hexadecyl methacrylate stabilized by MMs as the second network. As a result, the DN hydrogels that were toughened by MMs exhibited an excellent fracture strength of 1.48 MPa and a fracture strain of 2100%. Moreover, the hydrogels exhibited rapid recoverability and fatigue resistance. Therefore, the strategy would open up a novel avenue for the toughening of DN hydrogels for biomedical applications.
Xiu Yan Ren,Zhe Yu,Baijun Liu,Xue Jiao Liu,Ya Jun Wang,Qiang Su,Guang Hui Gao
Traditional hydrogels with poor mechanical properties have the largest barrier for extensive practical applications, such as artificial tendons, cartilage, skin and so on. In this work, a novel design strategy is proposed and demonstrated to improve the mechanical behavior of hydrogels by introducing ductile macromolecular microspheres (MMs) as crosslinking centers. Firstly, the MMs are synthesized, using butyl acrylate as the main component and dicyclopentyl acrylate as an intermolecular crosslinker, by a conventional emulsion polymerization method. Then acrylamide (AM) and hexadecyl methacrylate (HMA) are crosslinked by the MMs in water to form MM crosslinked poly(acrylamide-co-hexadecyl methacrylate) (P(AM/HMA)–MM) hydrogels. From the tensile measurements, the P(AM/HMA)–MM hydrogels exhibit dramatic enhancement of fracture stress σf (0.555 MPa) and fracture strain εf (5533%) when compared to the original P(AM/HMA) hydrogels. Furthermore, the P(AM/HMA)–MM hydrogels also have excellent puncture resistant properties. Based on traditional mechanisms of rubber-toughened plastics, it is clear that MMs can not only prevent the further development of cracks but can also be stretched to deform and absorb a large amount of energy. It is envisioned that this novel strategy, inspired by a toughening mechanism, will be an effective approach to enhance the mechanical properties and broaden the range of applications for hydrogels.
A novel route to construct stable and durable anti-adhesion surfaces was explored via a combination of the excellent anti-adhesion performance of zwitterionic betaine macromolecules with the strong adhesion of DOPA or its derivatives to various substrates. The zwitterionic betaine macromolecules bearing a thiol group poly(DMAPMAPS-co-BAC) and a DOPA derivative DMA containing a catechol anchor group and a double bond were first designed and synthesized. The poly(DMAPMAPS-co-BAC)-grafted surfaces were then fabricated via the interfacial thiol–ene photoclick reaction between poly(DMAPMAPS-co-BAC) and DMA anchored onto substrate (i.e., Glass slides and flat PET sheets) surfaces. The chemical formation of each layer on the surfaces was confirmed by XPS and ATR-FTIR analyses. Their morphologies and wettability were characterized. The results indicate that, compared with the original surfaces, the modified surfaces possess an increased nanoscale roughness; the WCA and OCA values on the modified Glass/PET surfaces can reach 10°/12° and 156°/162°, respectively, showing their strong hydrophilicity and excellent underwater superoleophobicity. The anti-oil-fouling and antifogging properties were investigated and the anti-bacterial adhesion properties were evaluated by bacterial adhesion tests using E. coli and S. aureus as test bacteria, respectively. The results show that the modified surfaces possess obvious anti-oil-fouling and antifogging properties and a strong ability to resist bacterial adhesion with a long term stability. It suggests that such a facile yet universal strategy based on interfacial thiol–ene photoclick chemistry could offer an effective solution to the poor stability of anti-adhesion surfaces modified with ultralow-adherent zwitterionic betaine macromolecules, and could be applicable to a wide variety of substrates.
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