Low-cost synthesis of silicon-doped graphene (Si-graphene) is attractive for the development of new graphene/geopolymer nanocomposites. In this work, a new insight into the properties of Si-graphene and the working mechanisms of Si-graphene in geopolymer is provided via molecular dynamics simulations. It is shown that Si-doping deteriorates the mechancial properties of graphene as Si-doping creates point defects, but it improves the surface hydrophilicity, which promotes its dispersion in aqueous media. By studying the polymerization process of Al(OH)₄/Si(OH)₄ monomers on Si-graphene, it is found that Si-graphene can be chemically bonded with geopolymer matrix by typical condensation reactions. Structural analysis reveals that the interfacial bonding has a beneficial effect on condensing the geopolymer composites, due to a denser interphase region. The tensile test reveals that the Young’s modulus of 10% Si-graphene/geopolymer nanocomposites is twice larger than that of graphene/geopolymer nanocmopistes. In addition, interfacial bonding can strengthen the interface structure and arrest crack formation in geopolymer matrices.

低成本合成硅掺杂石墨烯（Si-石墨烯）对于开发新型石墨烯/地质聚合物纳米复合材料具有吸引力。在这项工作中，通过分子动力学模拟，对硅石墨烯的性质以及硅石墨烯在地质聚合物中的工作机理有了新的认识。结果表明，硅掺杂会降低石墨烯的机械性能，因为硅掺杂会产生点缺陷，但会改善表面亲水性，从而促进其在水性介质中的分散。通过研究Al（OH）₄ / Si（OH）₄的聚合过程在Si-石墨烯上的单体上，发现Si-石墨烯可以通过典型的缩合反应与地质聚合物基质化学键合。结构分析表明，由于相间区域较密，界面键合对凝结地质聚合物复合物具有有益的作用。拉伸测试表明，10％Si-石墨烯/地质聚合物纳米复合材料的杨氏模量是石墨烯/地质聚合物纳米复合材料的杨氏模量的两倍。另外，界面结合可以加强界面结构并阻止地质聚合物基体中的裂纹形成。