Figure 1. Hierarchically-ordered chitin microstructure in an arthropod cuticle.

(a) (I) Plywood structure of chitin nanofibrils, (II) chitin nanofibrils in the matrix (CaCO₃ or proteins), (III) crystalline and amorphous domains of chitin nanofibril structure, and (IV) chitin structural formula. (b) Calcium-saturated methanol disintegrates chitin nanofibrils with minimal chemical modification, generating a Ca-methanol gel (disordered) (bottom-left panel). Ca²⁺ are removed from the Ca-methanol gel by washing with alcohol (methanol or IPA) and DI water, thus generating alcohol gels (methanol gel or IPA gel) in the N phase (bottom-middle panel) and a hydrogel in the N* phase (bottom-right panel). The yellow, pink, and blue beads represent three different types of solvent molecules: methanol-solvated Ca²⁺, alcohol (methanol or IPA), and water.