Gelation process of nanosilica sol and its mechanism: Molecular dynamics simulation

作者：Wen, Liyang; Xu, Jianchang; Yang, Qian; Zhang, Fusheng; Li, Fangbai; Zhang, Lijuan^*

来源：Chemical Engineering Sciences, 2020, 216: 115538.

DOI：10.1016/j.ces.2020.115538

• Nanosilica sol
• Gelation process
• Molecular dynamics simulation
• Polycondensation reaction

The spontaneous gelation tendency of nanosilica sol (NSS) greatly affects its application as a raw material in chemical production. Therefore, disclosing the gelation process and mechanism of NSS plays a vital role in effectively regulating the gelation process. Herein, we bring deep insight into the gelation process of NSS which mainly includes four stages: Short silicon oxide chains (Si-O chains) are formed on the surface of nanosilica particles. Si-O chains gradually grow into the solution. Si-O chains are intertwined and connected to the surface of the nanosilica particles. The 3D network gel structure is formed by using Si-O chains as a skeleton. The effect of silanol ionization on the gelation process and its mechanism was further explored. According to our results, appropriately increasing the ionization degree of silanol groups on silica surface or decreasing the ionization degree of silicic acids will greatly decrease the gelation process of NSS.

• 单位
  广东省生态环境与土壤研究所