Hollow chitosan hydrogel tube with controllable wrinkled pattern via film-to-tube fabrication

Due to mechanical instability, surface wrinkles form spontaneously in plants, animals and human beings for propagation and enhanced surface functionality. However, there remains tremendous challenge in mimicking such exquisite structure at a micro/nanoscale in lab. Herein, we report an approach to converting an electrodeposited chitosan hydrogel film into a hollow tube with controllable wrinkle wavelength and amplitude via soaking the film in acidic sodium dodecyl sulfate (SDS). Notably, wrinkled pattern can be controlled by a self-design device through modulating the shrinkage ratio. The resultant wrinkled hydrogel tube with adjustable wall thickness, outer diameter shows excellent mechanical strength, anti-fatigue ability, recoverability and flexibility. It is demonstrated that 2D/3D complicated hollow framework with wrinkled pattern can be customized on demand. This facile strategy not only provides a feasible approach to preparing hydrogel tube with wrinkles, but also points to possible pathways for bioengineering more complicated materials from natural polymers.