Reversible menthol-based coating for conservation and transparent screening of cellulosic artworks

Screen coatings serve as important conservation materials for protecting cultural heritage from external influences, particularly during abrupt environmental changes. However, the present conservation materials have the disadvantages of opaque, irreversibility, complex implementation and high cost. In this work, a screen coating with desired properties is simply designed by co-crystallization based on widely used sublimable conservation material, menthol and menthyl lactate. The physic-chemical properties are tuned by changing material types and rations. Co-crystallization products are characterized from phase states, volume change and crystal structure. Menthol/menthyl lactate (90:10) mixture form solid solution which only shows 1 % volume shrinkage during solidification. And, the screen coating can shelter paper sample from water and oxygen. Also it is transparent. The transparency can be attributed to poor crystallinity of the mixture coating, which reduces the light scattering. Also, the coating does not affect sample's mechanical strength after sublimation. Our work opens a way to develop new conservation material with new technology based on widely used conservation material.