Lightweight, Strong, Hydrostable, Bendable, Rolled‐Up, and Biodegradable Straws Enabled by Nano‐ and Microarchitecture Tuning of the Wood Cell Wall and Molecular Welding Strategy

Abstract Plastic pollution has become a global environmental challenge. Specifically, plastic straws are widely discarded and do not naturally decompose. Paper straws, as alternatives, suffer from weak mechanical strength, poor water/beverage stability, and lack of bendability. Here, an all‐natural plastic substitute is fabricated using a top‐down approach. After lignin is selectively removed from a natural wood slice, the delignified wood is infiltrated with chitosan solution. The chitosan‐infiltrated wood, in its wet state, is highly flexible, moldable, and can be rolled into desired shapes. After drying, strong hydrogen bonds form at the cellulose/chitosan interfaces, making it an all‐natural plastic substitute. By enclosing two sides using a chitosan adhesive, an all‐natural straw is produced with a superior mechanical strength of 242 MPa, higher than polypropylene and paper straws. After baking, the all‐natural straws show high water stability and maintain high mechanical strength in water (136 MPa) and carbonated beverages (71 MPa) for >2 days. A water‐moldable process also creates accordion‐like joints, giving the all‐natural straws superior bendability (120°) and compressibility (50%). The all‐natural straws exhibit high biocompatibility, full biodegradability in 5 months, and high circularity. Overall, the eco‐friendly fabrication of all‐natural straws holds great potential in addressing the ongoing pollution of plastic straws.