Controlled Synthesis of PDMS-Based Block Polymers for Durable Protection of Sandstone Cultural Relics

Cultural relics embody human vitality and creative wisdom; however, they are suffering irreversible damage, while the limited durability of existing protective materials remains insufficient to satisfy the practical requirements of heritage conservation. This study reports the fabrication of a block copolymer, PDMS-b-PGMA-b-PMPS, using ATRP methods for achieving durable protection of sandstone cultural relics. The optimized copolymer demonstrated remarkable hydrophobic properties (glass: 110°; sandstone: 140°) and adhesion strength (3.40 MPa). Compared with the acetone-based system, the chloroform-derived coating displayed improved hydrophobic properties and adhesive strength, while retaining the original appearance of sandstone through high transparency exceeding 80% and minimal color variation (ΔE < 5). Furthermore, the treated sandstone revealed remarkable resistance to salt-damping-heat and freeze-thaw cycles. The chloroform-derived coating demonstrated outstanding long-term durability, significantly surpassing both the untreated substrate and the acetone-formulated counterpart. Hence, this study successfully developed an efficient protective material, providing valuable guidance for the rational design of durable conservation materials for porous inorganic cultural heritage.