Anti-Icing Functional Biphilic Surfaces And Functionalized Multiscale Metal Organic Framework-Based Coatings

Ice formation is a major challenge for engineering systems. In this dissertation, it is aimed to provide understanding about fundamentals of ice formation, ice accumulation and de-icing, to identify the governing mechanisms and to develop surfaces and coatings for antiicing applications. In this thesis, a functionalized metal-organic framework (ZIF-8) based micro-nanosubnano scale coating (SHMC) with CA>172°, rolling angle <5°, and CAH<3° was developed. The coating was applied to metallic substrates by the practical spray coating method. Superimposed nanoparticles and porous structure of ZIF-8 created a surface morphology containing a significant number of airpockets. This thesis proves the superiority of SHMC over current approaches. Static and dynamic anti-icing behavior of SHMC was vigorously investigated. A fractal theory-based model of water contact angle was adapted to reveal its non-wetting mechanism. SHMC extended the icing time by at least 300% and maintained its superhydrophobicity for more than 30 icing/deicing cycles. The generated capillary pressure ranges within the multiscale coating were studied. The three-phase contact line characteristics were assessed. A significant reduction in heat transfer during the droplet contact time was obtained with SHMC. Furthermore, this thesis provides valuable information about de-icing behavior of biphilic surfaces. The results indicated that the biphilic surface consisting of superhydrophobic islands with the diameter of D=500 μm on a hydrophilic substrate having the superhydrophovity ratio of 19.62% was capable of complete passive cleaning due to the Laplace pressure gradient generated by this specific surface design. Furthermore, as the superhydrophobicity ratio increased, more delay in ice formation and accumulation occurred. The results show that the choice of the surface design is a compromise between its icing and de-icing behavior

Effect of membrane surface wetting on the performance of direct contact membrane distillation for seawater desalination

Membrane distillation (MD) is a standalone process to generate fresh water and is especially attractive when low-grade waste heat or renewable thermal energy is available. Surface wetting hinders the commercialization of Membrane distillation (MD) technology by deteriorating the permeate quality, thermal efficiency, and transmembrane flux. There is still a lack of understanding on how and to what extent the partially wetted membranes affect the performance of direct contact MD (DCMD) systems. It is of great importance to optimize the operating conditions under such conditions. The DCMD performance was addressed in the literature by considering non-wetted or fully wetted membranes. This study for the first time proposes a computational model to investigate the effect of membrane surface wetting ratio (R = Lwet/Ltotal) on the transmembrane (J) and thermal efficiency (η) of a DCMD module. Parametric and sensitivity analyses were performed to display the effect of system parameters (feed temperature, feed velocity, permeate temperature, permeate velocity, membrane thickness, and membrane surface wetting ratio) on the Key Performance Indicators (KPIs) of the DCMD module. The obtained results indicate that the permeate side temperature has more effect (more than twice) on KPIs in wetted membranes (∼30% and ∼15% rise in J and η) compared to the non-wetted ones (∼15% and ∼5% enhancement in J and η), and the negative effect of membrane surface wetting could be minimized by adjusting the permeate side operational conditions. The effect of membrane wetting ratio on the performance of the DCMD module in thin membranes (≤0.2 mm) and thick membranes (≥0.25 mm) strongly depends on the permeate and feed temperatures. The parametric and sensitivity analysis performed in this study will be beneficial to optimizing the operational conditions of MD systems for maximizing their performance and could serve as valuable guidelines in the development of efficient water desalination systems

Antifreeze proteins: a tale of evolution from origin to energy applications

Icing and formation of ice crystals is a major obstacle against applications ranging from energy systems to transportation and aviation. Icing not only introduces excess thermal resistance, but it also reduces the safety in operating systems. Many organisms living under harsh climate and subzero temperature conditions have developed extraordinary survival strategies to avoid or delay ice crystal formation. There are several types of antifreeze glycoproteins with ice-binding ability to hamper ice growth, ice nucleation, and recrystallization. Scientists adopted similar approaches to utilize a new generation of engineered antifreeze and ice-binding proteins as bio cryoprotective agents for preservation and industrial applications. There are numerous types of antifreeze proteins (AFPs) categorized according to their structures and functions. The main challenge in employing such biomolecules on industrial surfaces is the stabilization/coating with high efficiency. In this review, we discuss various classes of antifreeze proteins. Our particular focus is on the elaboration of potential industrial applications of anti-freeze polypeptides

Multiscale Superhydrophobic Zeolitic Imidazolate Framework Coating for Static and Dynamic Anti‐Icing Purposes

Abstract Ice formation is a major challenge for engineering systems. Superhydrophobic surfaces constitute an effective approach to address this challenge. However, in addition to complex preparation methods, surface texture‐ and chemistry‐related shortcomings reduce their effectiveness. In this study, a functionalized metal–organic framework (ZIF‐8) based micro‐nano‐subnano scale coating (SuperHydrophobic Multiscale Coating – SHMC) with CA (contact angle) > 172°, rolling angle 30 icing/deicing cycles. The generated capillary pressure ranges within the multiscale coating are studied. The three‐phase contact line characteristics including contact times, contact diameters, and interfacial heat transfer during droplet impact are assessed. A numerical model is developed using dynamic contact angle physics for transient heat transfer during the impact. Compared to the plain surface, which leads to instant icing at 60 ms after impact, no icing is observed on the developed coating. At least an order of magnitude reduction in heat transfer rate during the droplet contact time is obtained with SHMC

Early-stage ice detection utilizing high-order ultrasonic guided waves

Ice detection poses significant challenges in sectors such as renewable energy and aviation due to its adverse effects on aircraft performance and wind energy production. Ice buildup alters the surface characteristics of aircraft wings or wind turbine blades, inducing airflow separation and diminishing the aerodynamic properties of these structures. While various approaches have been proposed to address icing effects, including chemical solutions, pneumatic systems, and heating systems, these solutions are often costly and limited in scope. To enhance the cost-effectiveness of ice protection systems, reliable information about current icing conditions, particularly in the early stages, is crucial. Ultrasonic guided waves offer a promising solution for ice detection, enabling integration into critical structures and providing coverage over larger areas. However, existing techniques primarily focus on detecting thick ice layers, leaving a gap in early-stage detection. This paper proposes an approach based on high-order symmetric modes to detect thin ice formation with thicknesses up to a few hundred microns. The method involves measuring the group velocity of the S1 mode at different temperatures and correlating velocity changes with ice layer formation. Experimental verification of the proposed approach was conducted using a novel group velocity dispersion curve reconstruction method, allowing for the tracking of propagating modes in the structure. Copper samples without and with special superhydrophobic multiscale coatings designed to prevent ice formation were employed for the experiments. The results demonstrated successful detection of ice formation and enabled differentiation between the coated and uncoated cases. Therefore, the proposed approach can be effectively used for early-stage monitoring of ice growth and evaluating the performance of anti-icing coatings, offering promising advancements in ice detection and prevention for critical applications

A novel hybrid damage monitoring approach to understand the correlation between size effect and failure behavior of twill CFRP laminates

Despite the presence of numerous studies about size effect in composite materials, controversy still exists regarding the relation between mechanical behavior and size of the laminates. Therefore, in this study, a comprehensive experimental approach using combined structural health monitoring techniques namely, acoustic emission, digital image correlation and infrared thermography is conducted to elucidate the physics behind size effect in twill woven carbon fiber reinforced polymeric composites. Laminates with different thicknesses are produced and tested under tensile and in-plane shear loading conditions. In depth analysis of the acoustic emission data shows that an increase in the thickness of laminate changes the fraction of microdamage related to fiber failures. Moreover, a noticeable stagnation period in acoustic emission activity prior to global failure is observed for thick samples which is negligible for thin specimens. Furthermore, analysis of damage accumulation rate via acoustic emission technique is cross validated with digital image correlation and thermography for tensile and shear test results. The full field monitoring results indicate the inverse relation between the thickness of the laminates and damage growth rate. The combined usage of damage monitoring techniques shows that thicker laminates experiences slower damage growth dynamics as compared to those of thin laminates, thereby, assisting to understand the size effect in laminated composites

Development and Implementation of Microbial Antifreeze Protein Based Coating for Anti‐Icing

Abstract Ice formation on a solid surface is a major challenge in industrial applications, it causes higher energy consumption and performance deterioration and may lead to catastrophic results. The preparation of anti‐icing surfaces to prohibit ice accumulation on a surface is crucial to reduce operational costs and to extend the surface's lifetime. The utilization of cryoprotectants to obtain anti‐icing surfaces is an effective method and is applicable in multiple fields. Antifreeze proteins (AFPs) are natural cryoprotectants to obtain anti‐icing surfaces, which have the ability to decrease the freezing point and to prevent ice‐crystal growth via thermal hysteresis (TH) and ice recrystallization inhibition (IRI). This study reports the molecular cloning, expression, and production of AFP protein from Escherichia coli (E. Coli). This wok also demonstrates the activity of coated AFP on aluminum surfaces. The expressed AFP is immobilized on aluminum surfaces treated by oxygen plasma. The coated AFP exhibits promising antifreeze activity with a high anti‐icing ability on aluminum surfaces in the size of evaporator fins (40 × 40 cm). The outcome of this study provides new insights into the biotechnological implementation of AFPs to various industrial applications for energy‐saving and higher performance

A review on passive and active anti-icing and de-icing technologies

Icing introduces significant damage to aviation and renewable energy installations. High voltage transmission lines, wind turbine blades, and airplane and helicopter blades often suffer from icing phenomenon, which causes severe energy losses and impairs aerodynamic performance. There are a significant number of different studies proposing de-icing and anti-icing techniques. It is noticeable that the vast majority of these methods are oriented towards a particular area, and their adaptation to other areas is problematic. These methods often use various technologies, have different specifications, and sometimes lack clear interpretation of efficiency. This review presents a comprehensive overview of the most common de-icing and anti-icing technologies and identifies their benefits and limitations. Two major groups of de-icing and anti-icing methods were covered: passive and active methods. Among the passive methods, chemical methods, biochemical methods, and paint coatings, which either weaken the ice adhesion or shift the freezing point of a surface, were discussed in detail. The reviewed active methods include the hot air method, resistive method, infrared method, and microwave heaters, as well as the expulsive method, pneumatic method, water jet method, and high-power ultrasonic de-icing as mechanical methods. Passive methods lead to a limited performance under severe freezing, are often too expensive to cover large surfaces, and their effectiveness degrades over time, while active techniques cause high energy consumption and require intervention in the structure's design, and they are also more effective and provide a faster response, especially during severe freezing. It can be noted that various parameters impact the effectiveness of de-icing and anti-icing techniques for different applications. These parameters are limited to physical and chemical properties of the aimed engineering surfaces, environmental factors, severity of icing (clear, mixed, rime, crystal, etc.), size of the affected area and functionality of the whole energy system and should be thoroughly investigated and be taken into consideration in order to achieve a feasible, effective and economical de-icing or anti-icing approach for each application

Experimental failure analysis and mechanical performance evaluation of fiber-metal sandwich laminates interleaved with polyamide-6,6 interlayers through the combined usage of acoustic emission, thermography and microscopy techniques

Fiber-metal laminates are hybrid sandwich composite structures made of thin metallic sheets and layers of fiber-reinforced plastics. In this study, for the first time, the effects of polyamide 66 nonwoven interlayers on the tensile, three-point bending, interlaminar shear strength, and low velocity impact responses of fiber-metal laminates are investigated by coupling acoustic emission, thermography, and microscopy techniques. The fiber-metal laminates are interleaved with polyamide 66 nonwoven fabrics at two different areal weight density, namely, 17 gsm (grams per square meter) and 50 gsm. The tensile, bending, interlaminar shear strength, and low velocity impact tests are carried out in accordance with the ASTM standards. During the tensile and flexural tests, acoustic emission data are collected to understand damage types occurring under various loading conditions and, in turn, clearly shed light on the performance of polyamide 66 for interfacial strengthening in fiber-metal laminates. The results of acoustic emission investigation are correlated with the optical and scanning electron microscope-based microscopic analysis. It is shown that the interlaminar shear strength of fiber-metal laminates can be increased significantly (about 42%) by using polyamide 66 nonwoven interlayers. The impacted fiber-metal laminate specimens are examined to determine damage area and length using the lock-in thermography method. It is found that the polyamide 66 interlayers decrease the debonded length and damaged area up to 39 and 32%, respectively. The tensile and flexural strength and modulus of the fiber-metal laminate are not significantly affected by the presence of polyamide 66 interlayers, except a negligible drop in the value of tensile and flexural strength by 6 and 4%, respectively. The polyamide 66 interlayers are proved to be very successful in enhancing plastic deformation ability of the matrix and bonding efficiency between aluminum and composite sections

Upcycled graphene integrated fiber-based photothermal hybrid nanocomposites for solar-driven interfacial water evaporation

Solar-driven interfacial evaporation is an efficient and viable solution for providing freshwater, especially in remote areas that utilize sunlight for water purification and desalination systems. This study proposes a practical preparation method for a photothermal nanocomposite, compromising Polyacrylonitrile (PAN) nanofibrous membrane, crosslinked PVA, and upcycled Graphene Nanoplatelets (GNP). The synergistic effect between the PAN nanofibers and PVA/GNP nanocomposite and the contributing factors to the overall performance is examined. It was found that the initial thickness of the PAN nanofibrous layer has an inverse effect on the evaporation rate. The obtained results indicated that while the GNP content enhances the photothermal activity, it deteriorates the water absorbency of the nanocomposite; thus, an optimized concentration should be obtained. By investigating different parameters for the evaporator, we obtained an evaporation rate of 1.40 kg/m2h under 1 sun of illumination