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Corrosion and friction undulation caused by waterlubricated mechanical devices severely restricts the development of water-based lubricant in practical industries. In this paper, a kind of triazine-based covalent organic framework (TriC) nanomaterial is fabricated as the water-based lubricant additive, and two kinds of surfactant, namely, coconut diethanol amide (CDEA) and Tween 85 (T-85), were chosen carefully as water-based modifiers, respectively. Then, friction behaviors were evaluated using both composite dispersions as the lubricants, compared to either component alone, on an SRV-V tribometer under the high contact pressure. The dramatic reduction in friction coefficient (72.2% and 74.4%) and wear rate (98.0% and 95.8%) is shown by adding 0.1 wt % TriC into CDEA and T-85 aqueous solutions with 1% concentration in comparison with the pure water. More importantly, the perfect anticorrosion on the worn surface of the steel disk is observed during the rubbing process. Subsequently, the preferably competitive adsorption of TriC on the surface of friction pair and two uniquely assembled film configurations depended on surfactant structure are proposed to elaborate the opposite difference in friction and wear resistance as well as perfect anticorrosion.

Tribofilm configuration under the boundary lubrication region is an essential concern to gain insight into the tribological enhancement of the two-dimensional (2D) nano materials toward base oils. In this work, several alkyl carboxylic acids modified 2D triazine-based covalent organic frameworks (ATC) nano platelets were fabricated and served as lubrication additives. When carbon atoms add up to 16, the best lubricating performance is exhibited at an additive concentration of 0.05 wt % and the friction coefficient and wear volume are, respectively, reduced by 56.0% and 89.6% as compared to those of pure PAO 10 base oil. The analysis of the focused ion beam-transmission electron microscope (FIB-TEM) on the worn surface reveals that an alternately multilayer tribofilm consisting of 2D platelet additives and oxides and/or metallic soap salts is formed on the frictional interface of steel substrate, with a well-ordered arrangement along the sliding direction, which dominates the contributions of the excellent lubrication.

In order to solve the problems of traditional plastic packaging materials like poor degradability and insufficient active packaging function, this study successfully designs and synthesizes tannic acid (TA)-titanium (Ti) dual network coated hydrotalcite-like layered clay (LDHs@TA-Ti) and catechol grafted chitosan (C-CS) based on the principle of mussel bionics. And a novel idea is first put forward to fabricate LDHs@TA-Ti/C-CS/polyvinyl alcohol (PVA) nanocomposite films by solution casting method. The result of infrared and thermal analysis indicate that strong interfacial interaction is formed in the nanocomposites, which leads to the limitation of molecular chain movement and the increase of glass transition temperature. Although the addition of LDHs@TA-Ti significantly increases the crystallization temperature, the crystallinity does not change significantly. The water resistance, UV barrier, tensile strength and antibacterial properties of the final nanocomposite films are improved significantly, and all the films show good transparency in the visible range. Especially when the addition amount of LDHs@TA-Ti reaches 1 wt%, compared with C-CS/PVA composite film, the UV (at 300 nm) barrier property and tensile strength are increased by 36.3% and 45.1% respectively. Therefore, LDHs@TA-Ti/C-CS/PVA nanocomposite films show great potential as environmentally friendly active packaging films or coatings in extending the shelf life of food products.

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