Cribellate thread production as model for spider’s spinneret kinematics

AbstractSpider silk attracts researchers from the most diverse fields, such as material science or medicine. However, still little is known about silk aside from its molecular structure and material strength. Spiders produce many different silks and even join several silk types to one functional unit. In cribellate spiders, a complex multi-fibre system with up to six different silks affects the adherence to the prey. The assembly of these cribellate capture threads influences the mechanical properties as each fibre type absorbs forces specifically. For the interplay of fibres, spinnerets have to move spatially and come into contact with each other at specific points in time. However, spinneret kinematics are not well described though highly sophisticated movements are performed which are in no way inferior to the movements of other flexible appendages. We describe here the kinematics for the spinnerets involved in the cribellate spinning process of the grey house spider, Badumna longinqua, as an example of spinneret kinematics in general. With this information, we set a basis for understanding spinneret kinematics in other spinning processes of spiders and additionally provide inspiration for biomimetic multiple fibre spinning.

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Macromolecule Orientation in Nanofibers

Nanomaterials ◽

10.3390/nano8110918 ◽

2018 ◽

Vol 8 (11) ◽

pp. 918 ◽

Cited By ~ 17

Author(s):

Dan Tian ◽

Chun-Hui He ◽

Ji-Huan He

Keyword(s):

Molecular Structure ◽

Mechanical Properties ◽

Laminar Flow ◽

Fluid Mechanics ◽

Dragline Silk ◽

Natural Silk ◽

Spider Dragline Silk ◽

Spinning Process ◽

Spun Fiber ◽

Morphology And Mechanical Properties

Electrospinning is now commercially used for the fabrication of nano/micro fibers. Compared with spider dragline silk, artificial fibers have poor mechanical properties. Unlike natural silk, which has a hierarchical structure with an approximate 3-fold symmetry, the molecular structure of spun fiber has neither folding nor orientation. To date, it is almost impossible to control molecule orientation during the spinning process. Here, we show that macromolecule orientation can be easily controlled using the laminar flow of fluid mechanics. A lasting laminar flow in a long needle can order macromolecules. We find that the orientation of macromolecules can greatly affect the morphology and mechanical properties of fibers. We expect our technology to be helpful for more sophisticated fabrication of fibers with ordered macromolecules and DNA-like twists.

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The molecular structure characteristics of long chain branched polypropylene and its effects on non-isothermal crystallization and mechanical properties

Polymer ◽

10.1016/j.polymer.2012.12.073 ◽

2013 ◽

Vol 54 (4) ◽

pp. 1455-1462 ◽

Cited By ~ 34

Author(s):

Wangyang Zhao ◽

Yajiang Huang ◽

Xia Liao ◽

Qi Yang

Keyword(s):

Molecular Structure ◽

Mechanical Properties ◽

Isothermal Crystallization ◽

Structure Characteristics ◽

Branched Polypropylene ◽

Long Chain ◽

Long Chain Branched Polypropylene

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Conversion of Lignocellulosic Biomass to Nanocellulose: Structure and Chemical Process

The Scientific World JOURNAL ◽

10.1155/2014/631013 ◽

2014 ◽

Vol 2014 ◽

pp. 1-20 ◽

Cited By ~ 141

Author(s):

H. V. Lee ◽

S. B. A. Hamid ◽

S. K. Zain

Keyword(s):

Molecular Structure ◽

Mechanical Properties ◽

Lignocellulosic Biomass ◽

Chemical Process ◽

Catalyst Design ◽

Natural Resistance ◽

Cellulose Crystallinity ◽

Biomass Recalcitrance ◽

Cellulose Accessibility ◽

High Cellulose

Lignocellulosic biomass is a complex biopolymer that is primary composed of cellulose, hemicellulose, and lignin. The presence of cellulose in biomass is able to depolymerise into nanodimension biomaterial, with exceptional mechanical properties for biocomposites, pharmaceutical carriers, and electronic substrate’s application. However, the entangled biomass ultrastructure consists of inherent properties, such as strong lignin layers, low cellulose accessibility to chemicals, and high cellulose crystallinity, which inhibit the digestibility of the biomass for cellulose extraction. This situation offers both challenges and promises for the biomass biorefinery development to utilize the cellulose from lignocellulosic biomass. Thus, multistep biorefinery processes are necessary to ensure the deconstruction of noncellulosic content in lignocellulosic biomass, while maintaining cellulose product for further hydrolysis into nanocellulose material. In this review, we discuss the molecular structure basis for biomass recalcitrance, reengineering process of lignocellulosic biomass into nanocellulose via chemical, and novel catalytic approaches. Furthermore, review on catalyst design to overcome key barriers regarding the natural resistance of biomass will be presented herein.

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The Effects of Material Strength, Stress Ratio, and Compressive Overload on the Threshold Behavior of a SAE1045 Steel

Journal of Engineering Materials and Technology ◽

10.1115/1.3225765 ◽

1985 ◽

Vol 107 (1) ◽

pp. 19-25 ◽

Cited By ~ 21

Author(s):

M. T. Yu ◽

T. H. Topper

Keyword(s):

Mechanical Properties ◽

Growth Rate ◽

Threshold Stress ◽

Stress Ratio ◽

Peak Load ◽

Load Level ◽

Material Strength ◽

Threshold Stress Intensity ◽

Threshold Behavior ◽

Rate Behavior

The fatigue crack growth rate behavior of a SAE1045 steel in the as received condition and four different quenched and tempered conditions was studied as a function of stress ratio and peak compressive overload. The threshold stress intensity behavior of the quenched and tempered conditions was not sensitive to changes of monotonic mechanical properties. The threshold decreased linearly with increasing positive stress ratio and compressive peak load level. As received ferritic-pearlitic SAE1045 steel was much more sensitive to stress ratio and compressive peak load than any of the quenched and tempered conditions studied.

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Relationship between the molecular structure and certain mechanical properties of oriented polymers

Polymer Mechanics ◽

10.1007/bf00857250 ◽

1972 ◽

Vol 5 (4) ◽

pp. 640-641

Author(s):

K. E. Perepelkin

Keyword(s):

Molecular Structure ◽

Mechanical Properties ◽

Oriented Polymers

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Theoretical investigation of polymer molecular structure influence on dielectric properties and mechanical properties

Polymers for Advanced Technologies ◽

10.1002/pat.5499 ◽

2021 ◽

Author(s):

Yuying Cao ◽

Weihua Cao ◽

Xiao Yang ◽

Changxin Liu ◽

Xiaowen Qi

Keyword(s):

Molecular Structure ◽

Mechanical Properties ◽

Dielectric Properties ◽

Theoretical Investigation

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PLA/Carbon Nanotubes Multifilament Yarns for Relative Humidity Textile Sensor

Journal of Engineered Fibers and Fabrics ◽

10.1177/155892501100600302 ◽

2011 ◽

Vol 6 (3) ◽

pp. 155892501100600 ◽

Cited By ~ 7

Author(s):

Eric Devaux ◽

Carole Aubry ◽

Christine Campagne ◽

Maryline Rochery

Keyword(s):

Mechanical Properties ◽

Carbon Nanotubes ◽

Electrical Conductivity ◽

Relative Humidity ◽

Melt Spinning ◽

Flexible Sensor ◽

Spinning Process ◽

Textile Sensor ◽

Multifilament Yarns

Polylactide (PLA) was mixed with 4 wt.% of carbon nanotubes (CNTs) to produce electrical conductive multifilament yarns by melt spinning process for humidity detection. Thanks to a variation of electrical conductivity, this flexible sensor could detect the moisture presence. The introduction of plasticizer was necessary to ensure higher fluidity and drawability of the blend during the spinning process. The plasticizer modifies the crystallinity and the mechanical properties of the yarns. The effectiveness of this sensor (PLA/4 wt.% CNTs fibres) sensitive to humidity, is optimal when the spinning conditions are adapted. In this way, the temperature and the rate of the drawing roll were reduced. The influence of these parameters on the crystallinity, the mechanical properties and the sensitivity of the yarns were studied. Once the appropriate spinning conditions found, one humidity sensitive yarn was processed and the repeatability and efficient reversibility of its sensitivity were highlighted.

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Hierarchical spidroin micellar nanoparticles as the fundamental precursors of spider silks

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1810203115 ◽

2018 ◽

Vol 115 (45) ◽

pp. 11507-11512 ◽

Cited By ~ 14

Author(s):

Lucas R. Parent ◽

David Onofrei ◽

Dian Xu ◽

Dillan Stengel ◽

John D. Roehling ◽

...

Keyword(s):

Liquid Crystalline ◽

Spider Silk ◽

Fiber Spinning ◽

Fiber Formation ◽

Natural Material ◽

Physical Form ◽

Spinning Process ◽

Black Widow Spiders ◽

Spider Silks

Many natural silks produced by spiders and insects are unique materials in their exceptional toughness and tensile strength, while being lightweight and biodegradable–properties that are currently unparalleled in synthetic materials. Myriad approaches have been attempted to prepare artificial silks from recombinant spider silk spidroins but have each failed to achieve the advantageous properties of the natural material. This is because of an incomplete understanding of the in vivo spidroin-to-fiber spinning process and, particularly, because of a lack of knowledge of the true morphological nature of spidroin nanostructures in the precursor dope solution and the mechanisms by which these nanostructures transform into micrometer-scale silk fibers. Herein we determine the physical form of the natural spidroin precursor nanostructures stored within spider glands that seed the formation of their silks and reveal the fundamental structural transformations that occur during the initial stages of extrusion en route to fiber formation. Using a combination of solution phase diffusion NMR and cryogenic transmission electron microscopy (cryo-TEM), we reveal direct evidence that the concentrated spidroin proteins are stored in the silk glands of black widow spiders as complex, hierarchical nanoassemblies (∼300 nm diameter) that are composed of micellar subdomains, substructures that themselves are engaged in the initial nanoscale transformations that occur in response to shear. We find that the established micelle theory of silk fiber precursor storage is incomplete and that the first steps toward liquid crystalline organization during silk spinning involve the fibrillization of nanoscale hierarchical micelle subdomains.

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