Silk-Based Multiple Shape Memory Organohydrogels

The hydrophilic and hydrophobic components of biological systems like tissues give them extraordinary properties such as freezing tolerance, elasticity, and adaptability. To achieve similar properties, materials scientists are searching for materials that combine these two opposing properties. Organohydrogels have a biphasic structure containing hydrophilic and hydrophobic regions and are produced by combining water and organic solvents. This duality offers them a variety of applications, including antifreeze materials, environmental engineering, and biomedical products. In this study, organogels were formed in microdomains by dispersing hydrophobic polymers, which have different numbers of side alkyl chain length (n=14, 16, 18) within a silk fibroin-based hydrogel phase. Silk fibroin is one of the most important and widespread proteins used in biomedical applications. Its exceptional mechanical properties, biocompatibility, and biodegradability contribute to its importance. Furthermore, the amphiphilic regions within silk fibroin's structure are the primary reason for its selection for this study. The prepared organohydrogels withstand compression over 90%, have a Young's modulus over 2 MPa, and exhibit effective shape memory and antifreeze properties. Because the use of ternary hydrophobic monomers results in a loss of multiple shape memory properties, the gluing method, which allows for the preparation of each hydrophobic region separately, was used in this study. The resulting organohydrogel exhibits multiple shape memory properties sensitive to temperatures of 40, 30, and 15°C.