磺化改性聚羧酸减水剂吸附行为的分子动力学模拟  

Molecular Dynamics Simulation of the Adsorption Behavior of Sulfonation Modification of Polycarboxylate Superplasticizer

作　　者：管佳男 刘少静 刘晓[2] 朱海堂 GUAN Jianan;LIU Shaojing;LIU Xiao;ZHU Haitang(College of Civil Engineering,Henan University of Engineering,Zhengzhou 451191;College of Materials Science and Engineering,Beijing University of Technology,Beijing 100124)

机构地区：[1]河南工程学院土木工程学院,郑州451191 [2]北京工业大学材料科学与工程学院,北京100124

出　　处：《硅酸盐学报》2024年第10期3283-3290,共8页Journal of The Chinese Ceramic Society

基　　金：国家自然科学基金青年基金项目(52302020);国家自然科学基金面上基金项目(52372020);河南省高等学校重点科研项目(24A560004);河南省科技攻关项目(242102230138)。

摘　　要：聚羧酸减水剂(PCE)的吸附行为是其性能发挥的关键,但现有的研究缺少从原子或分子尺度上揭示其吸附机制。采用全原子分子动力学(MD)模拟研究磺化改性PCE(PAA-g-PALS)和传统结构PCE(PAA-g-HPEG)在水泥浆体环境下的构象及界面连接的结构、动力学和稳定性的差异。结果表明:水泥浆环境下PAA-g-HPEG和PAA-g-PALS分别趋于梳状和网络状构象;磺化改性分散了PCE与基底的结合点的分布,提高了PCE与基底的结合力,使聚合物朝远离基底方向伸展,显著增大渗透体积(增大约132.64%)。本研究结果不仅从原子水平上为PCE的作用机制提供新的见解,还为促进水泥基材料高性能发展提供理论依据。Introduction Polycarboxylate superplasticizers(PCEs)become the most widely used admixture in concrete admixtures due to their advantages of high water reducing rate,low dosage,and strong molecular structure design ability.Adsorption of PCEs onto the surfaces of cement particles is a prerequisite for the dispersive performance of PCE molecules.Therefore,the influence of PCE molecules with different structures on the dispersion properties of cement slurry can be clarified via revealing the adsorption process of PCE and the conformation characteristics of PCE after adsorption.The adsorption process and the conformation of the adsorbed PCE both involve interfacial interactions between the organic and inorganic phases,which is a dominant factor affecting the overall properties of the material.The existing molecular dynamics(MD)simulations are applied to the PCEs to elucidate its working mechanism.However,the molecular size of these model PCEs is smaller than that typically used for industrial applications to reduce computation cost.Furthermore,only pure water is used,or only Na+,Ca2+and Cl−are added to mimic a cement pore solution.The methods above make the results unable to accurately reflect the adsorption mechanism of PCE.Therefore,to better understand and effectively control the performance of PCE,some in-depth studies in the atomic and molecular scales are needed.In this paper,the MD simulations were used for the molecular size of the model PCE,which was consistent with that of PCE commonly used for industrial applications and simulates cement pore solutions.In addition,the adsorption mechanism of sulfonation modification of PCE was also investigated via analyzing the structure,dynamics and stability of interfacial connections.Methods The MD simulations were carried out based on a software named Gromacs-4.6.7 and a conventional oplsaa force field with RESP charges.The UFF force field was used for the substrate.The equilibrium MD simulation was conducted under the NPT ensemble for a total run time of 20 ns at a

关 键 词：聚羧酸减水剂 磺化改性 吸附 界面 分子动力学模拟 

分 类 号：TU528.042.2[建筑科学—建筑技术科学]