  The spider silk is one of the most interesting bio-materials investigated in
the last years. One of the main reasons that brought scientists to study this
organized system is its high level of resistance if compared to other
artificial materials characterized by higher density. Subsequently, researchers
discovered that the spider silk is a complex system formed by different kinds
of proteins, organized (or disorganized) to guarantee the required resistance,
which is function of the final application and of the environmental conditions.
Some spider species are able to make different silks, up to twelve, having a
composition that seems to be function of the final use (i.e. dragline web,
capture web, etc). The aim of this paper is to analyze the properties of the
spider silk by means of a thermodynamic approach, taking advantage of the
well-known theories applied to polymers, and to try to underline and develop
some intriguing considerations. Moreover, this study can be taken as an example
to introduce and discuss the importance of the concept of optionality and of
the anti-fragile systems proposed by N. N. Thaleb in his book "Antifragile:
Things that gain from disorder".
