A novel bio-inspired leather material engineered from bacterial cellulose–collagen and epoxidized soybean oil–citric acid adhesive

Bacterial cellulose (BC) has emerged as a highly promising candidate for bio-inspired leather applications, owing to its renewable origin and excellent mechanical properties. However, its inherently high-water content (up to 98%) and extensive hydrogen bonding network cause BC to become thin and brittle after drying, and susceptible to deformation upon rehydration. In this study, we developed a flexible and hydrophobic BC-based bio-inspired leather material by laminating a BC/Col (bacterial cellulose/collagen) surface layer onto a textile substrate using a novel bio-based adhesive. The adhesive, synthesized from epoxidized soybean oil (ESO) and citric acid (CA), requires no additional catalyst and exhibits excellent biodegradability. The bonding process effectively increases the thickness and flexibility of the BC/Col layer, while the ESO component significantly enhances its hydrophobicity. The resulting composite demonstrates excellent comprehensive performance: a tensile strength of 57.3 MPa with an elongation at break of 32.2%; an elastic recovery angle of 113.9°, with no visible creasing after repeated folding, indicating excellent flexibility and wrinkle resistance; and remarkable water resistance, as evidenced by a contact angle of 113.7° and an extended wetting time of 35 min. Furthermore, the bio-inspired leather material exhibits outstanding biodegradability, achieving a degradation rate of 69.77% after 150 days of soil burial. These findings offer a viable strategy for the development of environmentally friendly, high-performance BC/Col-based leather materials.