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  砂巖類文物是世界歷史文化遺產的重要組成部分，包括古建筑、石窟寺、石刻雕像和歷史紀念碑等。由于砂巖本身的特性以及戶外因素的影響，這類文物受溫度、濕度、水、可溶鹽、紫外線等的侵蝕，出現不同程度的劣化。為了保護這些文物，亟需開發合適的材料對其進行有效保護，保護或延緩這些因素造成的侵蝕和破壞。

  近期，西安交通大學和玲/潘愛釗課題組針對硅酸鹽材質的砂巖基石窟文物風化病害的特征及病害形成機理（砂巖內部膠結質流失）等問題，將膨潤土基抗膨脹水凝膠在砂巖基文物中原位形成以彌補流失的膠結質。首先通過組分和條件控制調控了膨潤土基水凝膠的原位形成時間和抗膨脹性，進而通過熒光示蹤技術研究了膨潤土基水凝膠材料在砂巖內部的分布，并深入評估了其在砂巖中的長效保護效果，最終研究了其戶外應用。該成果在期刊《ACS Applied Materials & Interfaces》上發表，題為“Insight into a Bentonite-based Hydrogel for the Conservation of Sandstone-based Cultural Heritage: In-situ Formation, Reinforcement Mechanism, and High-Durability Evaluation”的文章（DOI: https://doi.org/10.1021/acsami.2c13122）。

Figure 1. (a) Chemical structure scheme of B-H hydrogel. (b) Schematic illustration of the bentonite-based hydrogel (B-H) formed in-situ in sandstone.

Figure 2. Sandstones (a) after protecting with B-H and (b) traditional hydrogel.

Figure 3. (a) Chemical structure and optical images of the Carbon quantum dots (CQDs) used for fluorescent tracer. Photographs of the appearance (b), cross-sectional surface (b₁ and b₃) of the sandstones treated by hydrogel-CQDs. Photograph of the appearance (b₂) of the fresh sandstones. (c) Morphology and element distribution of Si, C and N elements in the internal grains of the treated sandstone by SEM-mapping. (d) Morphology of the internal grains of the treated sandstone by SEM. (e) Schematic diagram of in-situ formation of hydrogel inside the sandstone.

Figure 4. (a) Acid resistance, (b) salt crystallization cycles in moisture and heat, and (c) freeze-thaw cycles of unprotected and B-H-sandstone. (d) Schematization of the protecting mechanism for freeze-thaw resistance and salt resistance for B-H- sandstone.

Figure 5. Application of bentonite-based hydrogel on actual sandstone-based cultural heritage at Dafo Si. Sampling areas are indicated with red rectangles. Photographs of the sandstones before (a) and after (b) protecting by bentonite-based hydrogel.

  全文鏈接：https://pubs.acs.org/doi/full/10.1021/acsami.2c13122