Papers by Keyword: Spider Silk

Abstract: A body armor is vital for users in combat filed. Normally, the body armor have two components: soft and hard ones. This paper proposes feasibility assessment technique to evaluate contemporary materials: Kevlar, natural spider silk, and human hair, for making soft component of the body armor. There are four criteria: technical, economic, legal, and operational feasibilities to generate the feasibility assessment matrix. The optimal material in question is human hair which has highest rank at 82%.

Abstract: This brief communication proposes reasons for why larger β-sheet nanocrystals in spider silk exhibit lowered toughness as a function of increasing lateral size, but higher toughness as the β-strands are lengthened. Herein, this phenomenon is understood to be due to β-sheet stacking and the non-linear decreases in the electrostatic forces of attraction between β-sheets as more sheets are conjoined to form the crystal. Lengthening the β-strands raises the crystal toughness as a result of heightened electrostatic forces of attraction between the sheets. The extent of β-sheet nanocrystal toughness is a fractional balance between inter- and intramolecular bond strengths.

Abstract: Due to the exceptional biocompatibility of spider silk and poly-L-lactic acid (PLLA), electrospun PLLA or spidroin fiber mat is one of the best biomaterials. The diameter of electropun PLLA fiber decreased and mechanical property of such fiber mats was improved once some spidroin was added into PLLA/Hexaflorisopropanol (HFIP) solution. The influence of electrospinning voltage and distance on the shape and mechanical properties of spidroin/PLLA composite fibers was investigated as well as the molecular conformation and crystalline structure of the electrospun fibers. The results revealed that the diameter of spidroin/PLLA fiber was non-uniform, which varied from 300nm to 1000nm. The content of random coil or α-helix structure was about 45%, and spidroin presented a crystal structure separated with PLLA in their composite fibers. With the raise of voltage, the proportion of nano-sized fibers in an electrospun spidroin/PLLA fiber mat increased and tended to be unchanged. The breaking strength of the mat was improved following the increase of voltage. Meanwhile, the ratio of nano-sized fibers and initial modulus of the spidroin/PLLA fiber mat underwent the convex change against the electrospinning distance between the needle and collector.

Abstract: Silks spun by arthropods exhibit a set of unique properties that have emerged as the result of over four hundred million years of evolution. Silks show the most optimized combination of tensile strength and deformation at breaking, yielding the highest work of fracture of any known material. These outstanding features have thrust an increasing interest in reproducing or even improving the properties of natural silks. However, the advances in the field are hampered by an incomplete knowledge on the relation between microstructure and mechanical properties as well as by uncertainties related to the influence of processing in the performance of the fiber. In this work we present some of the most significant contributions of our groups to the field, stressing the possibility of controlling the tensile properties of silks and the contribution of this basic knowledge to the production of artificial regenerated fibers. Spider silk shows a large variability that it is thought to allow the spider to adapt the fibers to its immediate requirements, but represents a major drawback for its study or application. The development of the wet stretching process has allowed the modification of silk fibers in a controlled and reproducible way for the first time. Besides, recent improvements in the spinning of regenerated silkworm silk fibers have led to artificial fibers with properties that approach those of natural silks. These progresses allow envisaging the production of bioinspired fibers in a not too distant future.

Abstract: The spider silk is considered as a new type of biomaterials with its excellent mechanical properties. The mechanical properties of the spider silk are crucial to their applications. In this study the mechanical properties of spider silk were studied with a micro-tensile system driven by magnet-coil force actuator, which is very effective to measure the properties of low dimensional materials. The Young’s modulus of the spider silk is obtained, the relationship between the mechanical properties of spider silk and time is also acquired.