Acta Phys. -Chim. Sin. ›› 2010, Vol. 26 ›› Issue (11): 2907-2914.doi: 10.3866/PKU.WHXB20101110

• THERMODYNAMICS,THERMOCHEMISTRY AND SOLUTION CHEMISTRY • Previous Articles     Next Articles

Molecular Simulation of Dilute Polyacrylamide Solutions

LIU Yan-Yan1, CHEN Pan-Ke1, LUO Jian-Hui2, ZHOU Ge1,*, JIANG Bo1   

  1. 1. Key Laboratory of Green Chemistry and Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, P. R. China;
    2. Research Institute of Petroleum Exploration and Development of PetroChina, Beijing 100083, P. R. China
  • Received:2010-07-05 Revised:2010-08-05 Published:2010-10-29
  • Contact: JIANG Bo, ZHOU Ge E-mail:jiangbo@scu.edu.cn, zhougekk@scu.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (20904035).

Abstract:

Polyacrylamide (PAM) applied to various fields is an important class of linear water-soluble polymers. Therefore, it is of great significance to study the solution properties of PAM. We constructed solution models containing different amounts of water molecules with a mass concentration of about 1 g·mL-1. Using molecular dynamics (MD) simulations we calculated the radius of gyration (Rg) for non-ionic PAM (PAM-H) and anionic PAM (HPAM) in pure water and in aqueous solutions with different mass fractions of NaCl. We discussed their behaviors at different temperatures. We found that the salt tolerance of the polyacrylamides fromthe simulation agreed with the experimental results at different temperatures. Furthermore, the simulation results for all the solution models containing a different amount of water molecules basically showed a similar trend. Considering computational efficiency, the solution model containing 2000 water molecules was selected for our study. The radial distribution functions (RDF) for the oxygen ions and oxygen atoms of the HPAMchain were investigated in NaCl solution model containing 2000 water molecules. The reduced viscosity of HPAM solutions with increasing NaCl mass fractions and a better thickening ability as well as poor salt tolerance compared to PAM-H were explained considering their microstructures as determined by RDF.

 

Key words: Molecular dynamics, Polyacrylamide, Solution property, Radius of gyration, Radial distribution function

MSC2000: 

  • O645