Luo Qi, Huang Jiale
School of Materials Science and Engineering, Southeast University, Nanjing 211189, China.
Jiangsu Key Laboratory for Construction Materials, Southeast University, Nanjing 211189, China.
Materials (Basel). 2022 Jan 10;15(2):515. doi: 10.3390/ma15020515.
The critical issue of the durability of marine concrete lies in the continuous penetration and rapid enrichment of corrosive ions. Here a new ion transfer inhibitor, as TIA, with calcium silicate hydrate (C-S-H) interfacial affinity and hydrophobicity is proposed through insights from molecular dynamics into the percolation behavior of the ion solution in C-S-H nano-channels and combined with molecular design concepts. One side of the TIA can be adsorbed on the surface of the cement matrix and can form clusters of corrosive ions to block the gel pores so as to resist the ion solution percolation process. Its other side is structured as a hydrophobic carbon chain, similar to a door hinge, which can stick to the matrix surface smoothly before the erosion solution is percolated. It can then change into a perpendicular chain shape to reduce the percolation channel's diameter and thereby inhibit the percolation when ions meet the inhibitor. Therefore, once the erosion solution contacts TIA, it can quickly chelate with calcium ions and erosion ions at the interface to form clusters and compact pores. In addition, the water absorption, chloride migration coefficient, and chloride content of concrete samples decreased significantly after adding TIA, proving that TIA can effectively enhance the durability of cement-based materials. The structure-activity relationship of ion transfer that is proposed can provide new ideas for solving the critical problems of durability of cement-based materials and polymer molecular design.
海工混凝土耐久性的关键问题在于腐蚀性离子的持续渗透和快速富集。本文通过分子动力学对离子溶液在C-S-H纳米通道中的渗流行为的深入研究，并结合分子设计理念，提出了一种具有硅酸钙水合物（C-S-H）界面亲和力和疏水性的新型离子转移抑制剂TIA。TIA的一侧可吸附在水泥基体表面，形成腐蚀性离子簇以堵塞凝胶孔，从而抵抗离子溶液的渗流过程。其另一侧结构为疏水碳链，类似于门铰链，在侵蚀溶液渗流之前可顺利粘附在基体表面。然后它可以转变为垂直链状，减小渗流通道直径，从而在离子遇到抑制剂时抑制渗流。因此，一旦侵蚀溶液接触到TIA，它可以在界面处迅速与钙离子和侵蚀离子螯合形成簇并致密化孔隙。此外，添加TIA后混凝土试样的吸水率、氯离子迁移系数和氯离子含量均显著降低，证明TIA能有效提高水泥基材料的耐久性。所提出的离子转移结构-活性关系可为解决水泥基材料耐久性关键问题和聚合物分子设计提供新思路。
