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.

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.

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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 < 5°, and CAH (contact angle hysteresis) < 3° is developed and applied to metallic surfaces by spray coating. A fractal theory‐based model of contact angle is adapted to reveal its non‐wetting mechanism. SHMC extends the icing time by at least 300% and maintains its superhydrophobicity for > 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.

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