Spider silk is a protein fiber spun by spiders.

Spiders use their silk to make webs or other

IMPLIMENTATION IN DESIGN
structures, which function as sticky nets to
catch other animals, or as nests or cocoons to AS WE KNOW ACCORDING TO THE STATEMENT THE SPIDER SILK IS MUCH
protect their offspring, or to wrap up prey. STRONGER THAN STEEL IN COMPARISON TO STRENGTH AND ADHESIVENESS. SO
They can also use their silk to suspend WE CAN USE SPIDER SILK IN PLACE OF STEEL BARS (REINFORCEMENT) IN FRAMED
themselves, to float through the air, or to STRUCTURE BUILDINGS, IN TRUSSES AND IN SUSPENSION BRIDGES.
glide away from predators. REPLACEMENT OF STEEL WITH SPIDER SILK INCREASES THE STRENGTH OF THE
STRUCTURE. WE CAN ALSO REPLACE THE JOINTS OF BRIDGES AND TRUSSES BY
HOW DOES A SPIDER BUILT THE WEB ? STICKING IT TOGETHER (COHESIVE FORCE).
OR WE CAN MAKE A WHOLE STRUCTURE BY USING SPIDER SILK. SO THE
STRENGTH OF THE WHOLE STRUCTURE INCREASES MANY TIMES IN COMPARISON
LOAD DISTRIBUTION
TO NORMAL STRUCTURE. AND THE OF THE OVERALL BUILDING ALSO DECREASES,
WHICH IS ONE OF THE FACTOR WHICH INCREASES THE STRENGTH OF THE
BUILDING. IT CAN ALSO BE USED AS ROOFING MATERIAL FOR A LARGER SPAN LIKE
TYPES OF SPIDER WEB STADIUM, IF WE USE AS ROOFING SHEET.
C
O
N PHYSICAL PROPERTIES
C Spider silk is incredibly tough and is stronger by weight than
steel. Quantitatively, spider silk is five times stronger than steel of the same
E diameter. It has been suggested that a Boeing 747 could be stopped in flight by
a single pencil-width strand and spider silk is almost as strong as Kevlar, the Adhesive properties
P toughest man-made polymer. It is finer than the human hair (most threads are The stickiness of spiders' webs is courtesy of droplets of glue suspended on the silk
a few microns in diameter) and is able to keep its strength below -40°C. The threads. This glue is multifunctional – that is, its behavior depends on how quickly
T toughest silk is the dragline silk from the Golden Orb-Weaving spider (Nephilia something touching it attempts to withdraw. At high velocities, they function as an elastic
clavipes), so-called because it uses silk of a golden hue to make orb webs. solid, resembling rubber; at lower velocities, they simply act as a sticky glue. This allows
Spider silk is also very elastic and capture silk (sticky silk for catching prey) them to retain a grip on attached food particles.[18] The web is also electrically conductive
remains unbroken after being stretched 2-4 times its original length. Spider silk which causes the silk threads to spring out to trap their quarry, as flying insects tend to gain
is tougher, more elastic and more waterproof than silkworm silk so it could have a static charge which attracts the silk
a much wider range of applications. It is simple to see why spider silk is of such
interest to materials chemists since new ultra-strong fibres based on the silk Structure of spider silk. Inside a typical fiber there are crystalline
could be developed. regions separated by amorphous linkages. The crystals are beta-
sheets that have assembled together
CHEMICAL STRUCTURE AND PROPERTIES
Silks, as well as many other biomaterials, have a hierarchical structure (e.g., cellulose, hair). The primary structure is its amino acid sequence, mainly consisting of highly repetitive
glycine and alanine blocks,[25][26] which is why silks are often referred to as a block co-polymer. On a secondary structure level, the short side chained alanine is mainly found in the
crystalline domains (beta sheets) of the nanofibril, glycine is mostly found in the so-called amorphous matrix consisting of helical and beta turn structures.[26][27] It is the interplay
between the hard crystalline segments, and the strained elastic semi-amorphous regions, that gives spider silk its extraordinary properties.[28][29] Various compounds other than
protein are used to enhance the fiber's properties. Pyrrolidine has hygroscopic properties which keeps the silk moist while also warding off ant invasion. It occurs in especially high
concentration in glue threads. Potassium hydrogen phosphate releases protons in aqueous solution, resulting in a pH of about 4, making the silk acidic and thus protecting it
from fungi and bacteria that would otherwise digest the protein. Potassium nitrate is believed to prevent the protein from denaturing in the acidic milieu.[30]

AKSHAY SINGH
CONCEPT SHEET (BIOMIMICRY) 2015BAR002
B.ARCH 4TH SEM.