Composite Slow-Release Fouling Release Coating Inspired by Synergistic Anti-Fouling Effect of Scaly Fish

Inspired by the antifouling properties of scaly fish, the conventional silicone coating with phenylmethylsilicone oil (PSO/PDMS) composite coating was fabricated and modified with single layer polystyrene (PS) microsphere (PSO/PDMS-PS) arrays. The fish scale like micro-nano structures were fabricated on the surface of bio-inspired coating, which can reduce the contact area with the secreted protein membrane of fouling organisms effectively and prevent further adhesion between fouling organisms and bio-inspired coating. Meanwhile, PSO exuded to the coating surface has the similar function with mucus secreted by fish epidermis, which make the coating surface slithery and will be polished with the fouling organisms in turbulent waters. Compared to PSO/PDMS coating without any structure and conventional silicone coating, PSO/PDMS-PS showed better antiadhesion activity against both marine bacteria and benthic diatom (Navicula sp.). Additionally, the existence of PS microspheres can reduce the release rate of PSO greatly, which will extend the service life of coating. Compared to PSO/PDMS coating, the sustained release efficiency of PSO/PDMS-PS coating can reach 23.2%. This facile method for fabricating the bio-inspired composite slow-release antifouling coating shows a widely fabricating path for the development of synergistic anti-fouling coating.

Soft Gripper with EGaIn Soft Sensor for Detecting Grasp Status

With the Fourth Industrial Revolution, many factories aim for efficient mass production, and robots are being used to reduce human workloads. In recent years, the field of gripper robots with a soft structure that can grip and move objects without damaging them has attracted considerable attention. This paper proposes a variable-stiffness soft gripper, based on previous designs, with an added silicone coating for increased friction and an EGaIn soft sensor for monitoring grip forces. The variable-stiffness structure used in this study was constructed by connecting soft structures to rigid structures and using tendons fixed to the rigid structures. Furthermore, a more responsive EGaIn soft sensor compared to existing sensors was designed by adding bumps to the path traced by the alloy. After selecting the appropriate fingertip shape, changes in the output of the EGaIn soft sensor corresponding to the object held by the soft gripper were observed, confirming that the strength of the device could be changed according to the intended purpose.

Engineering of super bactericidal cotton using pyridinium/di-N-chloramine siloxane with intensified synergism

Tuning the ratio of complementary biocidal groups in a composite unit is proved to be a tactic to better minimize their weaknesses to realize higher synergism. A silane monomer, 6-(pyridin-4-yl)-3-(3-(trimethoxysilyl)propyl)-1,3,5-triazinane-2,4-dione, with biocidal precursors of one pyridinium and two N-chloramine sites was synthesized, hydrolyzed and dehydrocondensed on cotton cellulose. Specially, isonicotinaldehyde was ammonolyzed with biuret to produce 6-(pyridin-4-yl)-1,3,5-triazinane-2,4-dione that subsequently reacted with (γ-chloropropyl)trimethoxysilane to synthesize the silane monomer through nucleophilic substitution. The modifier on cotton was quaternized and chlorinated to transform the one pyridine and two amide N−H structures in each unit of the silicone to pyridinium and N-chloramine counterparts. The cationic pyridinium increases the hydrophilicity of the unit and electrically draws anionic bacteria to its two adjacent highly fatal N-chloramine sites, achieving a faster contact-killing rate than not only monofunctionality but also basic synergistic integration of one cationic center and one N-chloramine. This phenomenon is therefore referred to as “intensified synergism” and provides crucial information for the design of more powerful biocides. The pyridinium/di-N-chloramine silicone coating exhibited extraordinary durability towards UV irradiation, washing cycles and long-term storage due to the good UV resistance and chemical inertness of pyridinium and silicone backbone.

The Impact of the Underwater Hull Anti-Fouling Silicone Coating on a Ferry’s Fuel Consumption

There are well-known specifics of ro-pax ferry shipping, such as the time factor as a consequence of keeping a regular timetable and the priority given to minimizing heeling, pitching, and rolling caused by maximum focus on passenger comfort and ro-ro cargo safety. It is also extremely important to control the ferry’s fuel consumption, being one of the most important cost components. The aim of the article is to draw the attention of shipping company managers to the great potential that lies in the use of routine operational data, collected exclusively on board the ferries. It is worth noting that the research in this paper is based on standard office software packages rather than advanced statistical methods of data analysis, which are usually not accessible for shipping managers. Contrary to typical ocean-going vessels, there are a number of factors that need to be taken into consideration when analyzing ro-pax ferry fuel consumption. Moreover, these factors occur, in many cases, accidentally and, thus, they are difficult to observe on board the ferry without utilizing expensive and time-consuming methods. The possibility of fuel control is important not only for economic reasons but also due to air pollution caused by engine exhausts. The article presents an estimation of increased fuel consumption caused by the degradation of the hull silicone anti-fouling coating. The presented estimations of fuel consumption may be treated as the base for calculations of the economic effectiveness of ferries. The attempt to resolve the above-mentioned problem was made on the basis of research on a real ferry, which took place on the Świnoujście-Trelleborg line between 2007 and 2019.