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  砂巖類文物是世界歷史文化遺產(chǎn)的重要組成部分，包括古建筑、石窟寺、石刻雕像和歷史紀(jì)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(xiàn)不同程度的劣化。為了保護(hù)這些文物，亟需開發(fā)合適的材料對其進(jìn)行有效保護(hù)，保護(hù)或延緩這些因素造成的侵蝕和破壞。

  近期，西安交通大學(xué)和玲/潘愛釗課題組針對硅酸鹽材質(zhì)的砂巖基石窟文物風(fēng)化病害的特征及病害形成機(jī)理（砂巖內(nèi)部膠結(jié)質(zhì)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(bǔ)流失的膠結(jié)質(zhì)。首先通過組分和條件控制調(diào)控了膨潤土基水凝膠的原位形成時間和抗膨脹性，進(jìn)而通過熒光示蹤技術(shù)研究了膨潤土基水凝膠材料在砂巖內(nèi)部的分布，并深入評估了其在砂巖中的長效保護(hù)效果，最終研究了其戶外應(yīng)用。該成果在期刊《ACS Applied Materials & Interfaces》上發(fā)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