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Arnaud Antkowiak - One of the best experts on this subject based on the ideXlab platform.
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in drop capillary spooling of spider capture thread inspires hybrid fibers with mixed solid liquid mechanical properties
Proceedings of the National Academy of Sciences of the United States of America, 2016Co-Authors: Herve Elettro, Sebastien Neukirch, Fritz Vollrath, Arnaud AntkowiakAbstract:An essential element in the web-trap architecture, the capture Silk spun by ecribellate orb spiders consists of glue droplets sitting astride a Silk Filament. Mechanically this thread presents a mixed solid–liquid behavior unknown to date. Under extension, capture Silk behaves as a particularly stretchy solid, owing to its molecular nanosprings, but it totally switches behavior in compression to now become liquid-like: It shrinks with no apparent limit while exerting a constant tension. Here, we unravel the physics underpinning the unique behavior of this ”liquid wire” and demonstrate that its mechanical response originates in the shape-switching of the Silk Filament induced by buckling within the droplets. Learning from this natural example of geometry and mechanics, we manufactured programmable liquid wires that present previously unidentified pathways for the design of new hybrid solid–liquid materials.
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In-drop capillary spooling of spider capture thread inspires hybrid fibres with mixed solid-liquid mechanical properties
Proceedings of the National Academy of Sciences of the United States of America, 2016Co-Authors: Herve Elettro, Sebastien Neukirch, Fritz Vollrath, Arnaud AntkowiakAbstract:An essential element in the web-trap architecture, the capture Silk spun by ecribellate orb spiders consists of glue droplets sitting astride a Silk Filament. Mechanically this thread presents a mixed solid/liquid behaviour unknown to date. Under extension, capture Silk behaves as a particularly stretchy solid, owing to its molecular nanosprings, but it totally switches behaviour in compression to now become liquid-like: it shrinks with no apparent limit while exerting a constant tension. Here, we unravel the physics underpinning the unique behaviour of this " liquid wire " and demonstrate that its mechanical response originates in the shape-switching of the Silk Filament induced by buckling within the droplets. Learning from this natural example of geometry and mechanics, we manufactured novel programmable liquid wires that present novel pathways for the design of new hybrid solid-liquid materials. H ybrids made of different materials often display effective properties far exceeding those of their components (1): zinc-coated steel is both strong and corrosion-resistant, metal foams (hybrids of metal and air) are stiff, light and crush-able at the same time, making them perfect candidates to absorb energy in a car crash (2, 3). Nature also provides many exquisite examples of hybrid design such as the seashell nacre, both stiff and tough thanks to its inner 'brick-and-mortar' structure composed of rigid, though brittle, inclusions surrounded by a crack arresting soft organic matrix (4), or the bamboo stem with its hollow core and honeycomb-shaped cells that maximize the ratio of bending rigidity over weight (5). A most interesting natural hybrid material is the spi-der's capture thread, which consists of a core Filament that supports glue droplets. Here we report on the arresting mechanical behaviour of this capture thread, that changes from solid-like in extension to liquid-like in compression. We trace this behaviour back to the core Filament's buckling inside the droplets. A synthetic version of this natural system then allows us to copy the remarkable properties of spider's capture thread to a novel type of hybrid material. Spiders use different kinds of Silk to build their webs, and a typical ecribellate orb-web combines dry and smooth radial threads with wet and droplet-covered spiral threads (6, 7, 8, 9, 10). The adhesive nature of these droplets enables the spiral capture thread to perform its primary function of catching insect preys (6). Apart from being sticky, these capture threads also prove to be particularly resilient to tensile tests: extensive studies on their mechanical behaviour (11, 6) revealed that, when stretched, the thread elongates to three times its web-length without breaking and recoils back with no noticeable hysteresis or sagging when relaxed (12). This stretchiness confers spider Silk a strength tenfold that of natural or synthetic rubber (13, 14). These remarkable extensional properties rely on the macromolecular architecture of capture Silk (15, 16). The ability to cope with stretch is crucial for spider capture threads for it provides their unusually large toughness (energy required for rupture), which in turn allows them to absorb the kinetic energy of incident preys without breaking. Far less understood is the behaviour of the thread when compressed: unlike any solid fibre that sags or buckles, it keeps taut and self-adapts to compression. Figure 1 illustrates this singular behaviour, reminiscent of the response of liquid films to compression events: liquid films do not buckle upon squeezing, but rather self-adapt (17). And as for liquid films, self-adaptation for the capture thread is an indication for fibre self-tension. This liquid-like behaviour in compression suggests that more than merely endowing the web with adhesion, capture Silk might well have the additional mechanical function of preserving the web structural integrity. Indeed, without self-adaptation, single sticky strands would touch during relaxation events and thereby irremediably damage the web. With sagging suppressed, the sticky strands are secured apart.
Herve Elettro - One of the best experts on this subject based on the ideXlab platform.
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in drop capillary spooling of spider capture thread inspires hybrid fibers with mixed solid liquid mechanical properties
Proceedings of the National Academy of Sciences of the United States of America, 2016Co-Authors: Herve Elettro, Sebastien Neukirch, Fritz Vollrath, Arnaud AntkowiakAbstract:An essential element in the web-trap architecture, the capture Silk spun by ecribellate orb spiders consists of glue droplets sitting astride a Silk Filament. Mechanically this thread presents a mixed solid–liquid behavior unknown to date. Under extension, capture Silk behaves as a particularly stretchy solid, owing to its molecular nanosprings, but it totally switches behavior in compression to now become liquid-like: It shrinks with no apparent limit while exerting a constant tension. Here, we unravel the physics underpinning the unique behavior of this ”liquid wire” and demonstrate that its mechanical response originates in the shape-switching of the Silk Filament induced by buckling within the droplets. Learning from this natural example of geometry and mechanics, we manufactured programmable liquid wires that present previously unidentified pathways for the design of new hybrid solid–liquid materials.
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In-drop capillary spooling of spider capture thread inspires hybrid fibres with mixed solid-liquid mechanical properties
Proceedings of the National Academy of Sciences of the United States of America, 2016Co-Authors: Herve Elettro, Sebastien Neukirch, Fritz Vollrath, Arnaud AntkowiakAbstract:An essential element in the web-trap architecture, the capture Silk spun by ecribellate orb spiders consists of glue droplets sitting astride a Silk Filament. Mechanically this thread presents a mixed solid/liquid behaviour unknown to date. Under extension, capture Silk behaves as a particularly stretchy solid, owing to its molecular nanosprings, but it totally switches behaviour in compression to now become liquid-like: it shrinks with no apparent limit while exerting a constant tension. Here, we unravel the physics underpinning the unique behaviour of this " liquid wire " and demonstrate that its mechanical response originates in the shape-switching of the Silk Filament induced by buckling within the droplets. Learning from this natural example of geometry and mechanics, we manufactured novel programmable liquid wires that present novel pathways for the design of new hybrid solid-liquid materials. H ybrids made of different materials often display effective properties far exceeding those of their components (1): zinc-coated steel is both strong and corrosion-resistant, metal foams (hybrids of metal and air) are stiff, light and crush-able at the same time, making them perfect candidates to absorb energy in a car crash (2, 3). Nature also provides many exquisite examples of hybrid design such as the seashell nacre, both stiff and tough thanks to its inner 'brick-and-mortar' structure composed of rigid, though brittle, inclusions surrounded by a crack arresting soft organic matrix (4), or the bamboo stem with its hollow core and honeycomb-shaped cells that maximize the ratio of bending rigidity over weight (5). A most interesting natural hybrid material is the spi-der's capture thread, which consists of a core Filament that supports glue droplets. Here we report on the arresting mechanical behaviour of this capture thread, that changes from solid-like in extension to liquid-like in compression. We trace this behaviour back to the core Filament's buckling inside the droplets. A synthetic version of this natural system then allows us to copy the remarkable properties of spider's capture thread to a novel type of hybrid material. Spiders use different kinds of Silk to build their webs, and a typical ecribellate orb-web combines dry and smooth radial threads with wet and droplet-covered spiral threads (6, 7, 8, 9, 10). The adhesive nature of these droplets enables the spiral capture thread to perform its primary function of catching insect preys (6). Apart from being sticky, these capture threads also prove to be particularly resilient to tensile tests: extensive studies on their mechanical behaviour (11, 6) revealed that, when stretched, the thread elongates to three times its web-length without breaking and recoils back with no noticeable hysteresis or sagging when relaxed (12). This stretchiness confers spider Silk a strength tenfold that of natural or synthetic rubber (13, 14). These remarkable extensional properties rely on the macromolecular architecture of capture Silk (15, 16). The ability to cope with stretch is crucial for spider capture threads for it provides their unusually large toughness (energy required for rupture), which in turn allows them to absorb the kinetic energy of incident preys without breaking. Far less understood is the behaviour of the thread when compressed: unlike any solid fibre that sags or buckles, it keeps taut and self-adapts to compression. Figure 1 illustrates this singular behaviour, reminiscent of the response of liquid films to compression events: liquid films do not buckle upon squeezing, but rather self-adapt (17). And as for liquid films, self-adaptation for the capture thread is an indication for fibre self-tension. This liquid-like behaviour in compression suggests that more than merely endowing the web with adhesion, capture Silk might well have the additional mechanical function of preserving the web structural integrity. Indeed, without self-adaptation, single sticky strands would touch during relaxation events and thereby irremediably damage the web. With sagging suppressed, the sticky strands are secured apart.
Fritz Vollrath - One of the best experts on this subject based on the ideXlab platform.
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in drop capillary spooling of spider capture thread inspires hybrid fibers with mixed solid liquid mechanical properties
Proceedings of the National Academy of Sciences of the United States of America, 2016Co-Authors: Herve Elettro, Sebastien Neukirch, Fritz Vollrath, Arnaud AntkowiakAbstract:An essential element in the web-trap architecture, the capture Silk spun by ecribellate orb spiders consists of glue droplets sitting astride a Silk Filament. Mechanically this thread presents a mixed solid–liquid behavior unknown to date. Under extension, capture Silk behaves as a particularly stretchy solid, owing to its molecular nanosprings, but it totally switches behavior in compression to now become liquid-like: It shrinks with no apparent limit while exerting a constant tension. Here, we unravel the physics underpinning the unique behavior of this ”liquid wire” and demonstrate that its mechanical response originates in the shape-switching of the Silk Filament induced by buckling within the droplets. Learning from this natural example of geometry and mechanics, we manufactured programmable liquid wires that present previously unidentified pathways for the design of new hybrid solid–liquid materials.
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In-drop capillary spooling of spider capture thread inspires hybrid fibres with mixed solid-liquid mechanical properties
Proceedings of the National Academy of Sciences of the United States of America, 2016Co-Authors: Herve Elettro, Sebastien Neukirch, Fritz Vollrath, Arnaud AntkowiakAbstract:An essential element in the web-trap architecture, the capture Silk spun by ecribellate orb spiders consists of glue droplets sitting astride a Silk Filament. Mechanically this thread presents a mixed solid/liquid behaviour unknown to date. Under extension, capture Silk behaves as a particularly stretchy solid, owing to its molecular nanosprings, but it totally switches behaviour in compression to now become liquid-like: it shrinks with no apparent limit while exerting a constant tension. Here, we unravel the physics underpinning the unique behaviour of this " liquid wire " and demonstrate that its mechanical response originates in the shape-switching of the Silk Filament induced by buckling within the droplets. Learning from this natural example of geometry and mechanics, we manufactured novel programmable liquid wires that present novel pathways for the design of new hybrid solid-liquid materials. H ybrids made of different materials often display effective properties far exceeding those of their components (1): zinc-coated steel is both strong and corrosion-resistant, metal foams (hybrids of metal and air) are stiff, light and crush-able at the same time, making them perfect candidates to absorb energy in a car crash (2, 3). Nature also provides many exquisite examples of hybrid design such as the seashell nacre, both stiff and tough thanks to its inner 'brick-and-mortar' structure composed of rigid, though brittle, inclusions surrounded by a crack arresting soft organic matrix (4), or the bamboo stem with its hollow core and honeycomb-shaped cells that maximize the ratio of bending rigidity over weight (5). A most interesting natural hybrid material is the spi-der's capture thread, which consists of a core Filament that supports glue droplets. Here we report on the arresting mechanical behaviour of this capture thread, that changes from solid-like in extension to liquid-like in compression. We trace this behaviour back to the core Filament's buckling inside the droplets. A synthetic version of this natural system then allows us to copy the remarkable properties of spider's capture thread to a novel type of hybrid material. Spiders use different kinds of Silk to build their webs, and a typical ecribellate orb-web combines dry and smooth radial threads with wet and droplet-covered spiral threads (6, 7, 8, 9, 10). The adhesive nature of these droplets enables the spiral capture thread to perform its primary function of catching insect preys (6). Apart from being sticky, these capture threads also prove to be particularly resilient to tensile tests: extensive studies on their mechanical behaviour (11, 6) revealed that, when stretched, the thread elongates to three times its web-length without breaking and recoils back with no noticeable hysteresis or sagging when relaxed (12). This stretchiness confers spider Silk a strength tenfold that of natural or synthetic rubber (13, 14). These remarkable extensional properties rely on the macromolecular architecture of capture Silk (15, 16). The ability to cope with stretch is crucial for spider capture threads for it provides their unusually large toughness (energy required for rupture), which in turn allows them to absorb the kinetic energy of incident preys without breaking. Far less understood is the behaviour of the thread when compressed: unlike any solid fibre that sags or buckles, it keeps taut and self-adapts to compression. Figure 1 illustrates this singular behaviour, reminiscent of the response of liquid films to compression events: liquid films do not buckle upon squeezing, but rather self-adapt (17). And as for liquid films, self-adaptation for the capture thread is an indication for fibre self-tension. This liquid-like behaviour in compression suggests that more than merely endowing the web with adhesion, capture Silk might well have the additional mechanical function of preserving the web structural integrity. Indeed, without self-adaptation, single sticky strands would touch during relaxation events and thereby irremediably damage the web. With sagging suppressed, the sticky strands are secured apart.
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Thermally Induced Changes in Dynamic Mechanical Properties of Native Silks
2013Co-Authors: Juan Guan, David Porter, Fritz VollrathAbstract:Dynamic mechanical thermal analysis (DMTA) on individual native Silk fibers demonstrates changes in the dynamic mechanical properties of storage modulus and loss tangent as a function of temperature and temperature history ranging from −100 to 250 °C. These property changes are linked quantitatively to two main types of change in the Silk structure. First, the evaporation of water with increasing temperature up to 100 °C increases the storage modulus and removes two characteristic loss tangent peaks at −60 and +60 °C. Second, various discrete loss tangent peaks in the range 150–220 °C are associated with specific disordered Silk structures that are removed or converted to a limiting high-temperature relaxed structure by the combination of increasing temperature and static load in the DMTA tests. The results identify important origins of Silk Filament quality based on the analysis of measurements that can be traced back to differences in production and processing history
Sebastien Neukirch - One of the best experts on this subject based on the ideXlab platform.
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in drop capillary spooling of spider capture thread inspires hybrid fibers with mixed solid liquid mechanical properties
Proceedings of the National Academy of Sciences of the United States of America, 2016Co-Authors: Herve Elettro, Sebastien Neukirch, Fritz Vollrath, Arnaud AntkowiakAbstract:An essential element in the web-trap architecture, the capture Silk spun by ecribellate orb spiders consists of glue droplets sitting astride a Silk Filament. Mechanically this thread presents a mixed solid–liquid behavior unknown to date. Under extension, capture Silk behaves as a particularly stretchy solid, owing to its molecular nanosprings, but it totally switches behavior in compression to now become liquid-like: It shrinks with no apparent limit while exerting a constant tension. Here, we unravel the physics underpinning the unique behavior of this ”liquid wire” and demonstrate that its mechanical response originates in the shape-switching of the Silk Filament induced by buckling within the droplets. Learning from this natural example of geometry and mechanics, we manufactured programmable liquid wires that present previously unidentified pathways for the design of new hybrid solid–liquid materials.
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In-drop capillary spooling of spider capture thread inspires hybrid fibres with mixed solid-liquid mechanical properties
Proceedings of the National Academy of Sciences of the United States of America, 2016Co-Authors: Herve Elettro, Sebastien Neukirch, Fritz Vollrath, Arnaud AntkowiakAbstract:An essential element in the web-trap architecture, the capture Silk spun by ecribellate orb spiders consists of glue droplets sitting astride a Silk Filament. Mechanically this thread presents a mixed solid/liquid behaviour unknown to date. Under extension, capture Silk behaves as a particularly stretchy solid, owing to its molecular nanosprings, but it totally switches behaviour in compression to now become liquid-like: it shrinks with no apparent limit while exerting a constant tension. Here, we unravel the physics underpinning the unique behaviour of this " liquid wire " and demonstrate that its mechanical response originates in the shape-switching of the Silk Filament induced by buckling within the droplets. Learning from this natural example of geometry and mechanics, we manufactured novel programmable liquid wires that present novel pathways for the design of new hybrid solid-liquid materials. H ybrids made of different materials often display effective properties far exceeding those of their components (1): zinc-coated steel is both strong and corrosion-resistant, metal foams (hybrids of metal and air) are stiff, light and crush-able at the same time, making them perfect candidates to absorb energy in a car crash (2, 3). Nature also provides many exquisite examples of hybrid design such as the seashell nacre, both stiff and tough thanks to its inner 'brick-and-mortar' structure composed of rigid, though brittle, inclusions surrounded by a crack arresting soft organic matrix (4), or the bamboo stem with its hollow core and honeycomb-shaped cells that maximize the ratio of bending rigidity over weight (5). A most interesting natural hybrid material is the spi-der's capture thread, which consists of a core Filament that supports glue droplets. Here we report on the arresting mechanical behaviour of this capture thread, that changes from solid-like in extension to liquid-like in compression. We trace this behaviour back to the core Filament's buckling inside the droplets. A synthetic version of this natural system then allows us to copy the remarkable properties of spider's capture thread to a novel type of hybrid material. Spiders use different kinds of Silk to build their webs, and a typical ecribellate orb-web combines dry and smooth radial threads with wet and droplet-covered spiral threads (6, 7, 8, 9, 10). The adhesive nature of these droplets enables the spiral capture thread to perform its primary function of catching insect preys (6). Apart from being sticky, these capture threads also prove to be particularly resilient to tensile tests: extensive studies on their mechanical behaviour (11, 6) revealed that, when stretched, the thread elongates to three times its web-length without breaking and recoils back with no noticeable hysteresis or sagging when relaxed (12). This stretchiness confers spider Silk a strength tenfold that of natural or synthetic rubber (13, 14). These remarkable extensional properties rely on the macromolecular architecture of capture Silk (15, 16). The ability to cope with stretch is crucial for spider capture threads for it provides their unusually large toughness (energy required for rupture), which in turn allows them to absorb the kinetic energy of incident preys without breaking. Far less understood is the behaviour of the thread when compressed: unlike any solid fibre that sags or buckles, it keeps taut and self-adapts to compression. Figure 1 illustrates this singular behaviour, reminiscent of the response of liquid films to compression events: liquid films do not buckle upon squeezing, but rather self-adapt (17). And as for liquid films, self-adaptation for the capture thread is an indication for fibre self-tension. This liquid-like behaviour in compression suggests that more than merely endowing the web with adhesion, capture Silk might well have the additional mechanical function of preserving the web structural integrity. Indeed, without self-adaptation, single sticky strands would touch during relaxation events and thereby irremediably damage the web. With sagging suppressed, the sticky strands are secured apart.
Matteo Santin - One of the best experts on this subject based on the ideXlab platform.
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serum protein absorption on Silk fibroin fibers and films surface opsonization and binding strength
Journal of Bioactive and Compatible Polymers, 2002Co-Authors: Antonella Motta, Claudio Migliaresi, Andrew W Lloyd, Stephen Paul Denyer, Matteo SantinAbstract:Fibroin, the core of the Silk Filament protein, has been proposed as a biomaterial for different biomedical applications since it can be engineered as a thread, fabric or film. Infrared spectroscopy suggests that the dissolution of the fibroin Filaments and subsequent casting of the fibroin solution into films followed by treatment with methanol alters the protein structure leading to an increase in amorphous domains. The adsorption ofserum proteins on fabrics and films showed different hydrophobic binding strengths for the two materials with the protein binding being greatest for the more hydrophobic fibroin fibers. Differences between the materials were also observed in the adsorption of key immunoproteins. Although the C3 fragment of the complement system was adsorbed on both the surfaces, it appeared to be activated preferentially on the fibroin films and not on the fibroin fibers, whereas the Bb and C1q factors were only significantly present on the fibroin fabric. IgG appeared to be adsorbed, although to different extents, on both types of fibroin substrates. These results suggest that the biocompatibility of the Silk fibroin may be affected by changes in protein structure induced by processing the material.