Fabrication of porous three‐dimensional fibroin structures through a freezing process

Silk fibroin has been investigated for various biomedical applications. In this research, through a green process, without using freeze‐drying, which is energy consuming during a single step process that is completely aqueous‐based, without using any additional materials during or after structure formation, water‐insoluble silk fibroin sponges have been obtained; these achieved only through keeping fibroin solutions frozen at a suitable temperature for a sufficient time. The effect of solution concentration and freezing conditions on the pore morphology and size, microstructure, and mechanical properties was investigated. A discussion has been proposed for the formation of structures. The average measured pore sizes were approximately from 4 to 77 μm. Elastic modules of the investigated structures varied from about 100 to 900 kPa. Cyclic mechanical tests were performed; the remaining strain of the structures reached to about 1%. A less considered issue which can be considered as the possible significant change of the mechanical behavior of as‐prepared samples after one or more times of loading and unloading should be noted. The used method in this study as a cost effective and convenient procedure could have the potential for application in the production of porous structures for biomedical applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135 , 46537.