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(a) Ice adhesion strength and (b) sessile water contact angle of perfluoroalkane/alkane infused and uninfused PDMS gel.
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Infusion of solid perfluoroalkanes into polydimethylsiloxane gels provides a simple route to regenerating deicing surfaces, with low adhesion strength from the lower inherent cohesive energy of the perfluoroalkanes. Further, these surfaces are more hydrophobic and environmentally stable than their alkane analogues. The result is a robust, regenerat...
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... were tested through transverse shear applied to a column of ice on the substrate surface by a force transducer at À10 1C (full details supplied in the ESI †). Both AIGs and PIGs showed a dramatic reduction of the IAS compared to the pure PDMS (Fig. 3a); it should be noted that PDMS (108 kPa) is already an effective and commonly used icephobic coating. 25 The PIGs showed reasonably consistent values (31.7-19.6 kPa), with a broad trend of lower molecular weights providing lower IASs, as might be expected from the longer molecules having stronger van der Waals forces and thus cohesive ...
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... expected from the high intrinsic hydrophobicity PFAs, the water contact angle (CA) of the PIGs showed an increase in hydrophobicity (Fig. 3b, CA 96.51-100.11) compared to the neat PDMS surface (90.71), making it more suitable as a protective hydrophobic coating. These values appear broadly independent of molecular length, and lower than the pure PFAs (ca. 1161, ESI, † Fig. S4). In contrast, the lighter-alkane infused gels show a lessening of CA (77.11-83.71) compared to the PDMS, ...
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... rather than become exposed to the water by forming a new (sparingly soluble) surface layer. Conversely, the PIG in water (ESI, † Fig. S8) showed no any evidence of dissolution of the infused organic at any point, with no detectable dissolution after 2 weeks of soaking, as might be expected due to the increased hydrophobicity seen for the PIGs (Fig. ...
Citations
... Aizenberg et al. [18] developed another bioinspired strategy based on the Nepenthes pitcher plants, namely "slippery liquidinfused porous surface" (SLIPS), which have been developed with either fluorine based [ 18 , 19 ], fluorine-free organic lubricating compounds [ 20 , 21 ] aqueous based lubricating compounds [ 22 , 23 ], and even ferrofluids that are activated with a magnetic field [24] . This elegant approach has shown certain regenerative capability [19] , however, after a number of icing/de-icing cycles it tends to lose its icephobicity [21] , due to their two key limitations: the infused liquid tends to be drained away eventually and the highly porous structure required to host the infused liquid is prone to suffer mechanical failure. ...
Icephobic coatings are required for many applications in extremely cold environments, ranging from transport, communications, and infrastructure to energy systems. For practical applications, the ice adhesion strength (IAS) is the most suitable parameter to quantify the icephobicity of a coating, since ice would form on any surface if the conditions are extremely cold. From an engineering view point, an icephobic coating should also be robust, durable, environmentally friendly, and easy to apply over large and complex surfaces at a low cost. Here we report an epoxy based icephobic nanocomposite coating with the typical robustness of epoxy and an IAS as low as 9 ± 3 kPa. The superior icephobicity is provided by the incorporation of silane modified graphene nanoplatelets. Three different silanes are selected based on their low surface energy and their icephobic performance is discussed. The nanocomposite coatings are not only hydrophobic but also their low surface energy have allowed the IAS to be decreased dramatically, below the natural ice detachment threshold. The extraordinary robust icephobic nanocomposite coating reported herein remained icephobic after severe damage through abrasion. This study has demonstrated the potential use of low surface tension silanes for the development of highly robust icephobic coatings to be used in harsh and extreme cold environments.
... These coatings were named lubricated icephobic coatings (LICs) due to the lubricating additive in the coating structure [37]. The design was inspired by SLIPSs, aiming to enhance lubricant stability in icing environments [39]. Our previous work demonstrated the low ice adhesion behaviour of LICs in icing conditions. ...
Evaluating the performance of icephobic coatings interests various industries, such as aviation, maritime, energy, and transportation. Recent developments on icephobic coatings have consistently highlighted the need for durable icephobic surfaces in cold conditions. This study investigates the icing performance and durability of lubricated polymer coatings under cyclic icing/deicing tests. Coatings were made of polyethylene and a solid lubricant and manufactured using flame spray technology. Icing was performed by accreting ice in an icing wind tunnel. Deicing was conducted by removing ice with a centrifugal ice adhesion tester. Surface properties, such as surface morphology, roughness, wettability and chemical composition, were measured before and after the cyclic tests. The results showed stable icephobic behaviour for some coatings, while the performance of others decreased over the cycles. The cyclic tests caused mechanical damage to the surfaces, producing erosion, scratches and, for some coatings, surface cracks. These defects resulted in increased surface roughness and reduced hydrophobicity. However, no chemical changes were revealed for any of the surfaces. Moreover, the causes of cracks were attributed to the difference in thermal expansion behaviour of substrate and coating materials. This result highlights the importance of materials and process parameters selection in flame sprayed coatings designed for cold applications.
... The former consists of soft polymer networks infused with long chain alkanes throughout their volume. 25 −29 In these systems, the alkane wax, which could also be substituted with other compounds, such as (per)fluorinated liquids, 29 to enhance the properties of the material, will tend to migrate toward the interface and form a thin icephobic layer that can easily replenish itself when needed (in response to damage or lubricant leaching). 30 AIGs are therefore very robust systems also capable of achieving low ice adhesion forces. ...
Unwanted icing has major safety and economic repercussions on human activities, affecting means of transportation, infrastructures, and consumer goods. Compared to the common deicing methods in use today, intrinsically icephobic surfaces can decrease ice accumulation and formation without any active intervention from humans or machines. However, such systems often require complex fabrication methods and can be costly, which limits their applicability. In this study, we report the preparation and characterization of several slippery lubricant-infused porous surfaces (SLIPSs) realized by impregnating with silicone oil a candle soot layer deposited on double-sided adhesive tape. Despite the use of common household items, these SLIPSs showed anti-icing performance comparable to other systems described in the literature (ice adhesion < 20 kPa) and a good resistance to mechanical and environmental damages in laboratory conditions. The use of a flexible and functional substrate as tape allowed these devices to be stretchable without suffering significant degradation and highlights how these systems can be easily prepared and applied anywhere needed. In addition, the possibility of deforming the substrate can “allow” the application of SLIPS technology in mechanical ice removal methodologies, drastically incrementing their performance.
... Therefore, alternative surface designs with enhanced mechanical stability and durability are under consideration. One common strategy to solve liquid lubricant depletion consists of infusing solid lubricants within the coating structure, thus obtaining long-term icephobicity [23]. ...
In subzero conditions, atmospheric ice naturally accretes on surfaces in outdoor environments. This accretion can compromise the operational performance of several industrial applications, such as wind turbines, power lines, aviation, and maritime transport. To effectively prevent icing problems, the development of durable icephobic coating solutions is strongly needed. Here, the durability of lubricated icephobic coatings was studied under repeated icing/deicing cycles. Lubricated coatings were produced in one-step by flame spraying with hybrid feedstock injection. The coating icephobicity was investigated by accreting ice from supercooled microdroplets using an icing wind tunnel. The ice adhesion strength was evaluated by a centrifugal ice adhesion tester. The icing performance was investigated over four icing/deicing cycles. Surface properties of coatings, such as morphology, topography, chemical composition and wettability, were analyzed before and after the cycles. The results showed an increase in ice adhesion over the cycles, while a stable icephobic behaviour was retained for one selected coating. Moreover, consecutive ice detachment caused a surface roughness increase. This promotes the formation of mechanical interlocking with ice, thus justifying the increased ice adhesion. Finally, the coating hydrophobicity mainly decreased as a consequence of the damaged surface topography. In summary, lubricated coatings retained a good icephobic level after the cycles, thus demonstrating their potential for icephobic applications.
... The ice adhesion strengthen of aluminium alloy is 120-140 kPa [15]. Using SEDNA antiicing coatings, this can be reduced to less than 20 kPa [16], and the left ice can be easily removed using the deicing technique. Nevertheless, these effective levels are at a laboratorial level. ...
As the shipping routes of the Arctic have opened up comprehensively, with the reduction of the extent of the sea ice, the number of vessels using these routes has increased dramatically in order to take advantage of the shorter voyage times between the Pacific and Atlantic Oceans. This reduction in steaming time has the potential for positive impact on the environmental influence of global shipping through a reduction of greenhouse gas emissions. Yet the Arctic remains an incredibly unforgiving environment; its highly variable and dynamic ice conditions bring about risks to ships aiming to benefit from shorter routes.
To improve the safety and sustainability of Arctic shipping, SEDNA delivered five main technologies addressing the key challenges, including (a) a risk-based Arctic ship design framework, (b) anti-icing solutions, (c) a virtual-reality Arctic bridge, (d) an enhanced Arctic sea ice forecasting system and (e) an Arctic voyage planning tool.
The present report assesses the results of these deliverables. By comparing the developments with the previous status, it is demonstrated that the SEDNA technologies have resulted in substantial contributions, particularly in waterborne safety, the design and entire lifecycle of vessels, the environmental impact of shipping, and the circular economy:
• The SEDNA risk/goal-based design framework provides an approach to integrate the goal-based regulations of the Polar Code into a holistic design process. To this end, the framework provides the means to adapt the design of an Arctic ship to a specific Arctic route or operating area, considering that there are significant regional variations between different Arctic sea areas and that the operating conditions (e.g. ice conditions) in any Arctic sea area are subject to large inter- and intra-annual variations. To address key hazards, the approach makes use of a range of tools and approaches, including discrete-event simulations, semi-empirical and numerical design tools, full-scale ice load measurements, and accident data. The proposed holistic approach to ship design will minimise detrimental impacts over the entire life cycle of vessels operating in the Arctic, resulting in safer and more sustainable Arctic maritime operations.
• SEDNA anti-icing techniques reduce the influence of ice formation on vessel stability, communication equipment and on-board safety. Anti-icing coatings were developed using non-toxic materials and achieved effective de-icing with marginal cost.
• The SEDNA Arctic Bridge created a human-centred operational environment for the ice-going ship bridge using augmented reality technology to provide improved situational awareness and decision making. It provides increased safety and simplicity in the interaction between users, complex bridge-based systems, surrounding water and sea ice conditions and comprehensive navigation assistance.
• The SEDNA weather forecasting system enables 7 days’ prediction of Arctic ice conditions. It provides essential weather information ahead of time as input for safe and efficient Arctic ship navigation, with additional scope to be used as a tool for carrying out observations of climate change or for use in polar expeditions.
• The SEDNA voyage planning system integrates dynamic meteorological and oceanographic data with real-time ship monitoring and ice movement predictions to provide decision-making support for safe and efficient shipping-route optimisation.
Considering the growing body of knowledge about future ice coverage, seasonal weather patterns and predicted maritime activity levels, SEDNA developments are expected to be contribute to a safe and sustainable Arctic maritime environment. The developed technologies are not limited to academia and are currently being tested with industrial partners, as well as being used in consultations with international regulatory bodies. In addition, SEDNA developed cutting edge knowledge and techniques that offer opportunities for further development in both higher education and the broader research community.
... In a similar approach, perfluoroalkane wax infused gels has been tested for anti-icing. Due to the weaker intermolecular bonding between alkanes and water, this gel architecture provides greater omniphobicity with low ice-adhesion strength of 19.6 kPa [85]. ...
Non-wetting surfaces are of great importance due to its wider applicability in self-cleaning, condensation heat transfer, water collection, anti-frosting etc. In this regard, lotus leaf inspired superhydrophobic surfaces gained large interest towards fabrication of micro/nanostructured surfaces. However, the applicability of those surfaces limited itself with deteriorated performance upon accidental damages. Hence, an alternative approach of fabricating slippery lubricant infused porous surfaces inspired from Nepenthes Pitcher plant emerged with excellent capabilities. SLIPs presented liquid repellent property with sliding angles < 5°The present review article discusses about the recent development in SLIPs fabrication that possess excellent anti-icing ability. Furthermore, theoretical models for effective SLIPs design is investigated and discussed in detail. A comparison of theoretical and experimentally obtained results have been compared and presented. An outline of surface and lubricant characteristics to tune the interfacial characteristics is discussed followed by the limitations and possible future direction to achieve self-healing highly efficient SLIPs that can work under harsh conditions.
... For example, one common strategy consists of entrapping the liquid lubricant within a network of cross-linked elastomers [34,35]. Furthermore, lubricant in the form of solid is infused within the coating structure to improve lubricant stability and thus obtaining long-term icephobicity [36,37]. ...
... Inspired by the infusion of solid lubricant, we fabricated a composite coating, composed of a matrix material and a lubricating additive, hereafter termed lubricated icephobic coating (LIC). Lubricating additives, in the form of liquid oil [34,38], grease paste [17] and solid wax [36,39], have shown potential icephobic behaviour [40]. In the present study, the matrix material is made of low-density polyethylene (LDPE), previously used to produce flame sprayed icephobic coatings [41][42][43]. ...
Lubricated icephobic coatings were fabricated by flame spraying with hybrid feedstock injection. In this one-step process, composite coatings were produced by spraying a matrix material from a combustion flame spray gun and a lubricating additive from an injector, externally to the flame. External injection avoided possible thermal degradation of the heat sensitive additive during spraying. Inexpensive and widely available feedstock materials were used, polyethylene as the matrix and solid cottonseed oil as the lubricating additive. The coating properties were investigated by thermal and chemical analyses, surface roughness and wettability measurements at room temperature and in cold conditions. The icephobic behaviour was evaluated by accreting ice from supercooled water droplets in the icing wind tunnel. Ice adhesion was measured by the centrifugal ice adhesion test. The results showed that lubricant addition improved the icephobic performance of the coatings. Moreover, cooling the flame temperature with compressed air addition reduced thermal degradation of polymers. This was beneficial for the icephobic behaviour, thus lowering the shear ice adhesion strength down to 23 kPa ± 6 kPa. In conclusion, lubricated icephobic coatings were successfully produced by combining the hybrid feedstock injection and the thorough optimization of process parameters. This approach provides a potential surface engineering solution for the industrial sectors facing icing problems.
... [63] Similar results have been obtained by Clancy and co-workers using solid perfluoroalkanes as the lubricant to fabricate polydimethylsiloxane gels capable of regenerating deicing surfaces. [64] However, while functioning well, the easy loss of perfluoroalkanes into the environment would strongly hamper this use, especially given the success of simple paraffin wax. ...
Self‐healing antifouling materials have gained rapidly increasing interest over the past decade and have been studied and used in a rapidly increasing range of applications. Recent developments and challenges in self‐healing antifouling materials are summarized in four sections: first, the different mechanisms for both antifouling and self‐healing are briefly discussed. Second, three main categories of self‐healing antifouling materials based on surface replenishing and dynamic covalent and noncovalent interactions are discussed, with a focus on the preparation, characterization, and central characteristics of different self‐healing antifouling materials. Third, different types of potential applications of self‐healing antifouling materials are summarized, such as injectable hydrogels and oil/water separations. Finally, a summary of future development of the field is provided, and a number of critical limitations that are still outstanding are highlighted.
... If the ice adhesion strength is below the threshold of 100 or 10 kPa, the surfaces can be referred to as an icephobic or superlow ice adhesion surface, respectively. 11,12 In past years, several approaches, including decreasing water crystallization temperature, 13,14 delaying freezing time, 15−20 and lowering ice adhesion strength of surfaces, 2,6,11,12,21,22 have been adopted to create passive icephobic surfaces. In particular, superhydrophobic surfaces have been extensively investigated aiming to prevent supercooled water from freezing on surfaces, but the mechanical properties and/or interlocking effect of these textured surfaces are still challenges for icephobicity, restricting their application perspective. ...
Waxgels are known for their unique mechanism in generating sacrificial wax layers during anti-icing application. To address the severe slow regrowing of the wax layer, here, carbon black is incorporated...
