Robust Solid–Solid Phase Change Coating Encapsulated Glass Fiber Fabric with Electromagnetic Interference Shielding for Thermal Management and Message Encryption

Abstract Electromagnetic interference (EMI) shielding composites with both thermal response/management functions and message transfer/encryption behavior are ideal for use in fields such as aerospace, construction engineering, and military equipment. In this work, a self‐cross‐linking supramolecular solid–solid phase change polyethylene glycol (ScPEG) coating is prepared based on multiple hydrogen bonds, which is used for encapsulating glass fiber fabric (GFF) modified with silver nanowires (AgNWs). The solid–solid phase change coating is obtained through the hydrolysis‐condensation of PEG with a reactive silanol end group. Polyethylene glycol molecular chains can store and release heat by switching between the crystalline and amorphous state. The silanol groups can form supramolecular networks through the physical cross‐linking of multiple hydrogen bonds, resulting in an excellent thermal stability. In particular, hydrogen bonds between ScPEG and AgNW‐modified GFF (A‐GFF) enhance interfacial interactions, and the resulting robust structure enables an efficient stress transfer. ScPEG‐coated A‐GFF can achieve a tensile strength of up to 191 MPa and a tunable EMI shielding effectiveness (SE) of 40 to 72 dB depending on the number of fabric layers. Moreover, the fabric exhibits a flexible thermal response characteristic, an outstanding thermal management capability, and potential message encryption behavior.