Superhydrophobic Modification of Collagen Fiber: A Potential Substitute for Tanning

Tanning is considered to be the crosslinking reaction between collagen fibers and tanning agents, and a majority of tanning reactions result in suppressed water absorption and enhanced hydrophobicity of leather. However, extensive use of tanning agents may bring a burden to the environment. Herein, to facilitate a sustainable leather manufacturing industry, we propose a revolutionary strategy of "tanning" without tanning agents. Based on this strategy, superhydrophobic collagen fibers (FAS-CFs) were fabricated through dehydration, followed by superhydrophobic modification. Dehydration aimed to eliminate the "sticky" effect of water on collagen fiber to obtain a dispersed hierarchical structure. Superhydrophobic modification not only dispersed and stabilized the fiber structures, but also protected the fiber dispersity from water immersion. Compared with chrome -tanned collagen fibers (Cr-CFs) and glutaraldehyde-tanned collagen fibers (G-CFs), FASCFs showed higher hydrophobicity, lower water absorption, and superior mechanical properties. Meanwhile, FAS-CFs exhibited a high thermal denaturation temperature of 92.5 degrees C and retained their original shape after being heated to 100 degrees C. Therefore, our proposed strategy is expected to be a potential substitute for conventional tanning and might contribute to cleaner and sustainable leather manufacturing.