Chemical Research in Chinese Universities ›› 2023, Vol. 39 ›› Issue (6): 985-991.doi: 10.1007/s40242-023-3005-5

• Articles • Previous Articles     Next Articles

Spatial Correlation in Typical Binary Polycondensation Systems: An Essential Extension of the Kirkwood-Buff Theory

GU Fang1, LI Jiangtao1, HONG Xiaozhong2, and WANG Haijun1,3,4   

  1. 1. College of Chemistry and Materials Science, Hebei University, Baoding 071002, P.R. China;
    2. College of Physical Science and Technology, Hebei University, Baoding 071002, P.R. China;
    3. Chemical Biology Key Laboratory of Hebei Province, Hebei University, Baoding 071002, P.R. China;
    4. Key Laboratory of Medicinal Chemistry and Molecular Diagnosis, Ministry of Education, Hebei University, Baoding 071002, P.R. China
  • Received:2023-01-12 Online:2023-12-01 Published:2023-11-18
  • Contact: WANG Haijun, HONG Xiaozhong E-mail:whj@hbu.edu.cn;hxz@hbu.edu.cn
  • Supported by:
    This work was supported by the Natural Science Foundation of Hebei Province, China (No.B2022201050) and the Interdisciplinary Research Program of Natural Science of Hebei University, China (No.DXK202112).

Abstract: We present the isothermal susceptibility (XT) for the typical binary polycondensation system of Af -Bg type, and relate XT to the weight-average degree of polymerization in terms of the Kirkwood-Buff (KB) theory. The investigation is based on a new expression of XT for mixtures, which is still expressed by the KB integrals (KBIs) but endowed with an explicit physical interpretation. For polymerization systems, it is proposed that the KBIs can be further decomposed according to whether there exists a bond between particles when conversions (extents of reaction) of functional groups are incorporated into the KBIs. In this way, XT is directly decomposed into its relevant components as well. This is especially useful to reveal the relationship between local structures and average properties of various polymerization systems. As a consequence, the effect of polymerization on XT is greatly simplified in comparison with the free energy route. Therefore, we have provided a very simple method to carry out some thermodynamic properties of polymerization systems.

Key words: Isothermal compressibility, Polycondensation, Kirkwood-Buff theory, Radial distribution function, Spatial correlation