Constructing a Dual-Function Surface by Microcasting and Nanospraying for Efficient Drag Reduction and Potential Antifouling Capabilities

Abstract

To improve the drag-reducing and antifouling performance of marine equipment, it is indispensable to learn from structures and materials that are found in nature. This is due to their excellent properties, such as intelligence, microminiaturization, hierarchical assembly, and adaptability. Considerable interest has arisen in fabricating surfaces with various types of biomimetic structures, which exhibit promising and synergistic performances similar to living organisms. In this study, a dual bio-inspired shark-skin and lotus-structure (BSLS) surface was developed for fabrication on commercial polyurethane (PU) polymer. Firstly, the shark-skin pattern was transferred on the PU by microcasting. Secondly, hierarchical micro- and nanostructures were introduced by spraying mesoporous silica nanospheres (MSNs). The dual biomimetic substrates were characterized by scanning electron microscopy, water contact angle characterization, antifouling, self-cleaning, and water flow impacting experiments. The results revealed that the BSLS surface exhibited dual biomimetic features. The micro- and nano-lotus-like structures were localized on a replicated shark dermal denticle. A contact angle of 147° was observed on the dual-treated surface and the contact angle hysteresis was decreased by 20% compared with that of the nontreated surface. Fluid drag was determined with shear stress measurements and a drag reduction of 36.7% was found for the biomimetic surface. With continuous impacting of high-speed water for up to 10 h, the biomimetic surface stayed superhydrophobic. Material properties such as inhibition of protein adsorption, mechanical robustness, and self-cleaning performances were evaluated, and the data indicated these behaviors were significantly improved. The mechanisms of drag reduction and self-cleaning are discussed. Our results indicate that this method is a potential strategy for efficient drag reduction and antifouling capabilities.

Polydopamine-Assisted Immobilization of Chitosan Brushes on a Textured CoCrMo Alloy to Improve its Tribology and Biocompatibility

“…In recent years, cobalt and its alloys (e.g., the commercial cobalt chromium molybdenum (CoCrMo) alloy) have become well known for their orthopedic and dental applications. For orthopedic treatment, CoCrMo is commonly used in articulating load-bearing implants because of its high performance in wear resistance and corrosion resistance [1,2,3,4,5,6,7]. With aging of the population and an increase in active lifestyles, the demand for all these replacements is increasing [8].…”

A new biomimetic antifouling method based on water jet for marine structures

“…30 By combining the shark skin with the lotus surface, a dual-function surface was constructed to provide superhydrophobic, antidrag and self-cleaning properties. 31 The biomimetic lubricant-infused surfaces can generate better stability and antifouling effect when compared with simple microstructures. 32 However, either the simple microstructures or complex biomimetic surfaces are coated as static antifouling layers, which are unlikely to work effectively for a long period due to mechanical instability.…”

Forming of Dynamic Microstructure of Flexible Polymer

“…In addition, a precision mold is also time-consuming to fabricate. The model molding technology has developed rapidly in recent years, and the common microstructure component model molding technologies at present include plastics micro-injection molding [8,9], micro-thermoforming [10,11,12], micro-casting [13,14,15], and micro/nano imprinting [16,17,18,19,20,21,22,23,24,25,26,27,28,29,30]. While the aforesaid technologies have their characteristics and merits, most of them require molds for micro-molding processing.…”