Protocol for preparation of highly durable superhydrophobic bulks with hierarchical porous structures

Superhydrophobic surfaces face challenges in comprehensive durability when used in extreme outdoor environments. Here, we present a protocol for preparing nanocomposite bulks with hierarchical structures using the template technique. We describe steps for using hybrid nanoparticles of polytetrafluoroethylene and multi-walled carbon nanotube to fill inside and dip on the polyurethane (PU) foam. We then detail procedures for its removal by sintering treatment. The extra accretion layer on the PU foam surface was highlighted to construct hierarchical porous structures. For complete details on the use and execution of this protocol, please refer to Wu et al.

Porous bulk superhydrophobic nanocomposites for extreme environments

Robust superhydrophobic materials providing protections from harsh weather events such as hurricanes, high temperatures, and humid/frigid conditions have proven challenging to achieve. Here, we report a porous bulk nanocomposite comprising carbon nanotube (CNT)-reinforced polytetrafluoroethylene (PTFE). The nanocomposites are prepared using a templated approach by infusing a CNT/PTFE dispersion into a sponge followed by thermal annealing and decomposition of the sponge template. Importantly, an excess accretion of CNT/PFFE particle mixture on the sponge resulted in nanocomposites with unique and hierarchical porous microstructure, featuring nanochannels near the surface connected to microscale pores inside. The superhydrophobic nanocomposite could resist liquid jets impacting at a velocity of �85.4 m s1 (Weber number of �202,588) and exhibits excellent high-temperature resistance as well as mechanochemical robustness. The porous nanocomposites display excellent icephobicity both with and without infusion with polydimethylsiloxane/silicone oil. These properties should facilitate exploitation as stiff/strong structural polymeric foams used in a variety of fields

Application Status and Research Progress of Resin Matrix Composites in Unmanned Underwater Vehicle

Abstract Unmanned underwater vehicle (UUV) is a kind of underwater unmanned vehicle. In recent years, it has been widely used in civil and military fields. With the development of the unmanned underwater vehicle to multi-function, strong concealment, high performance and other directions, different kinds of resin matrix composite materials with excellent sound absorption, corrosion resistance, high specific strength characteristics, the utilization rate of unmanned underwater vehicle gradually increased and has broad development potential. In this paper, the application status and key technologies of resin-matrix composites in the field of unmanned aerial vehicle (UUV) are studied from two aspects of function and structure, and the technical trend of resin-matrix composites in the future UUV is described, and its development prospect is forecasted.</jats:p

Tensile properties of ply splice fiber reinforced composite laminates

To fabricate large-scale or unusually shaped composite structures, pieces of reinforcement plies can be spliced to match specific size and shape requirements, forming ply splice structures. The junction of different plies can be considered a defect in the final material, affecting the mechanical properties. In this paper, ply splice carbon fiber reinforced plastics were studied to analyze the fracture mechanism caused by the ply splice, including the effects of the junction geometry and the ply angle. Tensile tests were performed, assisted with digital image correlation for strain distribution analysis and acoustic emission for break mode analysis. The finite element method was also performed using ABAQUS software to study the fracture mechanism. In order to analyze the interlaminar fracture, the interface was simulated with cohesive elements. The results showed that, for a unidirectional carbon fiber reinforced plastics with ply splice, fracturing occurred first at the junction location and then at the interfaces between the splicing layers and the continuous layers. The final strength was determined by the number of continuous layers. The ply-angle had evident effects on the properties of carbon fiber reinforced plastics with ply splices. For a stacking sequence of [± 30°]5S, the effects of the ply splice on the strength and the fracture mode were similar to the effect with unidirectional plates. For a stacking sequence of [± 45°]5S, the ply splice had no effect on the fracture mode, but it did decrease the strength slightly. For a stacking sequence of [± 60°]5S, almost no effect of the ply splice structure could be observed. PACS (optional, as per journal): 75.40.-s; 71.20.LP </jats:p