The mechanical property of the fibroin also depends on their
internal structure. The fibroin MN's solidification process is due to the
loss of water from the fibroin matrix in dry condition by using fan
drying. During the fan drying process, a thin layer or skin is formed at
the air–water interface of the fibroin. This interface can reduce the
rate of evaporation of water and permit sufficient time for the fibroin
chains to self-assemble into internal crystalline structures.