Silkworm (Bombyx mori) cocoon vs. wild cocoon multi-layer structure and performance characterization

As protective shells for their biological functions against environmental damage and attack by natural predators, the silkworm (Bombyx mori) cocoon and its wild partner have distinctive multi-layer structures, which are systematically studied in this paper by the SEM, the thermogravimetric analyzer, and the Fourier transform infrared spectroscopy. Their mechanical properties are also investigated for the whole hierarchy and each cascade as well. In order to better demonstrate the superior survivability of cocoons in harsh environments, air permeability and moisture vapor transmission rate of the silkworm cocoon are tested. The results show the silkworm cocoons have excellent air permeability and moisture vapor transmission rate. A better understanding of different cocoons? bio-functions will be of particular importance to design thermal textiles and provide better comfort and safety for clothing in future.