Study of Photoinduced Electron Transfer Process in Ruthenium Complex Modified Zinc Oxide Nanoparticles by Ultrafast Time-Resolved Transient Absorption Spectroscopy

Near-Infrared Responsive Smart Superhydrophobic Coating with Self-Healing and Robustness Enhanced by Disulfide-Bonded Polyurethane

Synergistic self-healing materials and inorganic particles to create self-healing superhydrophobic surfaces for improving their robustness is a common technique, but the suitability between the two is rarely mentioned. In this work, we developed a multifunctional superhydrophobic coating with room-temperature stability, mechanical stability, self-healing, and NIR stimuli response, in which self-healing polyurethane (PU) serves as the interface reinforcement layer and poly(dopamine) (PDA)-coated flower-like ZnO composite particles serve as the hydrophobic layer. A series of temperature-dependent self-healing PU materials were designed and synthesized by regulating the ratio of hard and soft chain segments in PU, and the relationship between the healing temperature of PU and the hydrophobic stability of the composite coatings was investigated. Based on dynamic hydrogen and disulfide bonds, PUs displayed excellent self-healing performance. Thanks to the self-healing and interfacial strengthening effect of PU and the photothermal properties of PDA, the composite coating exhibits not only excellent mechanical stability but also rapid self-healing ability in response to NIR stimuli. Furthermore, the smart coating demonstrated superior self-cleaning and corrosion resistance. This work provides a reference for developing strong and stable water-repellent reversible superhydrophobic coatings with great potential and promising future.

Surface Grafting of Ru(II) Diazonium-Based Sensitizers on Metal Oxides Enhances Alkaline Stability for Solar Energy Conversion

The electrografting of [Ru(ttt)(tpy-C₆H₄-N₂⁺)]³⁺, where "ttt" is 4,4',4″-tri-tert-butyl-2,2':6',2″-terpyridine, was investigated on several wide band gap metal oxide surfaces (TiO₂, SnO₂, ZrO₂, ZnO, In₂O₃:Sn) and compared to structurally analogous sensitizers that differed only by the anchoring group, i.e., -PO₃H₂ and -COOH. An optimized procedure for diazonium electrografting to semiconductor metal oxides is presented that allowed surface coverages that ranged between 4.7 × 10^-8 and 10.6 × 10^-8 mol cm^-2 depending on the nature of the metal oxide. FTIR analysis showed the disappearance of the diazonium stretch at 2266 cm^-1 after electrografting. XPS analysis revealed a characteristic peak of Ru 3d at 285 eV as well as a peak at 531.6 eV that was attributed to O 1s in Ti-O-C bonds. Photocurrents were measured to assess electron injection efficiency of these modified surfaces. The electrografted sensitizers exhibited excellent stability across a range of pHs spanning from 1 to 14, where classical binding groups such as carboxylic and phosphonic derivatives were hydrolyzed.