Thermally deformable face seals and respirators including such face seals. The thermally deformable face seal structures comprise composite phase change materials that mold to the face of a user to provide a personalized but one-size-fits-all facial fit having excellent shape retention after use and long term durability. The phase change material is applied onto a base component to cover all or substantially all of the surface area of the base component and adapts to the face of the user to provide a secure, leak-free seal.