物理化学学报 >> 2009, Vol. 25 >> Issue (02): 223-228.doi: 10.3866/PKU.WHXB20090205

研究论文 上一篇    下一篇

二氟尼柳/水滑石插层组装结构、氢键及水合特性的分子动力学模拟

潘国祥; 倪哲明; 王芳; 王建国; 李小年   

  1. 浙江工业大学化学工程与材料学院, 杭州 310032
  • 收稿日期:2008-08-01 修回日期:2008-10-08 发布日期:2009-01-16
  • 通讯作者: 倪哲明 E-mail:jchx@zjut.edu.cn

Molecular Dynamics Simulation on Structure, Hydrogen-Bond and Hydration Properties of Diflunisal Intercalated Layered Double Hydroxides

PAN Guo-Xiang; NI Zhe-Ming; WANG Fang; WANG Jian-Guo; LI Xiao-Nian   

  1. College of Chemical Engineering and Materials Science, Zhejiang University of Technology, Hangzhou 310032, P. R. China
  • Received:2008-08-01 Revised:2008-10-08 Published:2009-01-16
  • Contact: NI Zhe-Ming E-mail:jchx@zjut.edu.cn

摘要: 采用分子动力学方法模拟二氟尼柳插层水滑石(DIF/LDHs)的超分子结构, 研究复合材料主客体间形成的氢键以及水合膨胀特性.结果表明, 当水分子总数与DIF分子总数之比Nw≤3时, 层间距dc保持基本恒定, 约1.80 nm; 当Nw≥4时, 层间距逐渐增大, 且符合dc=1.2611Nw+13.63线性方程. 随着水分子个数增加, 水合能驻UH逐渐增大. 当Nw≤16时, 由于⊿UH<-41.84 kJ·mol-1, LDHs-DIF可以持续吸收水, 从而使材料层间距不断膨胀. 但当Nw≥24时, ⊿UH>-41.84 kJ·mol-1, 此时LDHs-DIF层间不能再进一步水合, 因此LDHs-DIF在水环境中膨胀具有一定的限度. 水滑石层间存在复杂的氢键网络. DIF/LDHs水合过程中, 水分子首先同步与层板和阴离子构成氢键; 当阴离子趋于饱和后, 水分子继续与层板形成氢键, 并逐步发生L-W型氢键取代L-A型氢键, 驱使阴离子向层间中央移动, 与层板发生隔离; 最后水分子在水滑石羟基表面形成有序结构化水层.

关键词: 分子动力学模拟, 二氟尼柳/水滑石, 氢键, 水合

Abstract: The supramolecular structure of diflunisal intercalated layered double hydroxides (DIF/LDHs) was modeled bymolecular dynamics (MD)methods.Hydrogen bonding, hydration and swelling properties of DIF/LDHs were investigated. The interlayer spacing dc was found to be constant (ca 1.80 nm) when Nw(the ratio of the numbers of water molecule to DIF)≤3. The interlayer spacing dc gradually increases as Nw≥4 and this increase follows the linear equation dc =1.2611Nw+13.63. The hydration energy gradually increases as the water content increases. LDHs/DIF hydrates when Nw≤16 because hydration energy ⊿UH<-41.84 kJ·mol-1. At Nw≥24 the hydration of LDHs/DIF does not occur because ⊿UH>-41.84 kJ·mol -1. Swelling of LDHs/DIF is thus limited in an aqueous environment. The interlayer of DIF/LDHs contains a complex hydrogen bonding network. The hydration of DIF/LDHs occurs as follows: water molecules initially form hydrogen bond with layers and anions. While the anions gradually reach a saturation state and water molecules continue to form hydrogen bonds with the hydroxyls of the layers. The L-Wtype hydrogen bond gradually substitutes the L-A type hydrogen bond and the anions move to the center of an interlayer and then separate with the layers. Last, a well-ordered structural water layer is formed on the surface hydroxyls of DIF/LDHs.

Key words: Molecular dynamics simulation, Diflunisal/layered double hydroxide, Hydrogen-bond, Hydration

MSC2000: 

  • O641