Preparation of Fluorine-Free Superhydrophobic Paper with Dual-Response of Temperature and pH

Mechanical characteristics and antibacterial activity against Staphylococcus aureus of sustainable cellulosic paper coated with Ag and Cu modified ZnO nanoparticles

In this study, zinc oxide (ZnO) nanoparticles were prepared and modified using a wet chemical method with different concentrations of Ag and Cu nanoparticles. The objective was to improve the mechanical, optical, and antibacterial properties of the coated paper by using the prepared pigments. The long-term antimicrobial effects of the coated paper were evaluated over 25 years. The successful synthesis of a hexagonal structure of ZnO nanoparticles decorated with spherical Ag and Cu nanoparticles ranging from 20 to 50 nm was confirmed using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and transmission electron microscopy (TEM). By increasing the concentrations of Ag and Cu from 0.01% to 1.0%, the mechanical properties of the coated paper were enhanced. The tensile strength reached a maximum of 6.77 kN/m and 7.03 kN/m, elongation increased to 1.69% and 1.70%, tensile energy absorption improved to approximately 77 and 80 J/m2, and burst strength rose to 218 and 219 kPa, respectively. The use of Ag-modified ZnO maintains the optical properties, while Cu-modified ZnO reduces brightness and whiteness without affecting opacity. The antimicrobial inhibition activity was improved with higher silver (Ag) and copper (Cu) content. The formulations containing 1% Ag/ZnO and 1%Cu/ZnO showed long-lasting antibacterial effects against gram-positive Staphylococcus aureus bacteria. Even after 25 years of aging, they maintained inhibition rates of 92.2% and 62.2%, respectively. The molecular docking and GeneMANIA analysis revealed the potential of ZnO, Ag-modified ZnO, and Cu-modified ZnO nanoparticles to disrupt the S. aureus cell wall biosynthesis pathway by targeting the MurA enzyme and associated cell wall synthesis genes.

Surface modifications towards superhydrophobic wood-based composites: Construction strategies, functionalization, and perspectives

Amidst the burgeoning interest in multifunctional superhydrophobic wood-based composites (SWBCs) for their varied applications and the need for improved environmental resilience, recent efforts focus on enhancing their utility by integrating features such as mechanical and chemical stability, self-healing capabilities, flame resistance, and antimicrobial properties. Research indicates that various external conditions can influence the wettability and additional characteristics of SWBCs. This comprehensive review outlines three critical factors affecting SWBCs' performance: synthesis methods, wood taxonomy, and chemical agents. It further provides a detailed overview of SWBCs' specific attributes, including essential qualities for diverse applications and the limitations posed by different contexts. Additionally, it elaborates on performance evaluation techniques, offering a foundational framework for SWBCs' practical application. This work aims to serve as an important resource for future research and development in SWBC engineering.

Preparation of the Temperature-Responsive Superhydrophobic Paper with High Stability

In this paper, a method for preparing a high-stability superhydrophobic paper with temperature-induced wettability transition is proposed. First, a temperature-responsive superhydrophobic triblock polymer PHFMA-PTSPM-PNIPAAm was prepared by one-step polymerization of TSPM, HFMA, and NIPAAm in a mass ratio of 0.3:0.3:0.3, then a superhydrophobic paper with a good temperature response was successfully prepared by grafting amino-modified SiO₂ with the polymer to modify the surface of the paper. A further study found that when the mass ratio of amino-modified SiO₂ to polymer is 0.2, the coating has good superhydrophobicity and transparency. What is more, the prepared modified paper is in a superhydrophobic state when the temperature is higher than 32 °C, and is in a superhydrophilic state when it is lower than 32 °C, which can realize free conversion between superhydrophobic and superhydrophilic states. In addition, the superhydrophobic paper prepared by this method not only has high oil-water separation efficiency, and the superhydrophobic coating shows good stability and transparency, but also has low requirements of environmental conditions for preparation, relatively simple preparation process, and strong repeatability, and it has a very broad application prospect.