The molecular basis of CO2 interaction with polymers containing fluorinated groups:: computational chemistry of model compounds and molecular simulation of poly [bis(2,2,2-trifluoroethoxy)phosphazene]

被引:65
作者
Fried, JR [1 ]
Hu, N [1 ]
机构
[1] Univ Cincinnati, Dept Chem & Mat Engn, OBR Ctr Comp Aided Mol Design, Cincinnati, OH 45221 USA
基金
美国国家科学基金会;
关键词
carbon dioxide; solubility; molecular association;
D O I
10.1016/S0032-3861(03)00285-4
中图分类号
O63 [高分子化学(高聚物)];
学科分类号
070305 ; 080501 ; 081704 ;
摘要
Ab initio molecular orbital calculations of CO2 and model compounds have been used to identify the nature of specific interactions between CO2 and the fluorinated substituent groups of polymers such as poly(trifluoropropyl methyl siloxane) and poly[bis(2,2,2-trifluoroethoxy)phosphazene] (PTFEP) that exhibits high CO2 permeability and perm selectivity. Second-order Moller-Plesset (MP2) perturbation calculations (6-311++G** basis set) were used to obtain energies, dipole and quadrupole moments, and polarizabilities of CO2, three alkanes (CH4, CH3CH3, and CH3CH2CH3), and three fluoroalkanes (CF4, CH3CF3, and CH3CH2CF3 Results of energy calculations of three CO2-alkane and three CO2-fluoroalkane dimers indicate that CO2 forms a favorable quadrupole-dipole interaction with the fluoroalkyl groups. The maximum quadrupole-dipole interaction energy obtained was -11.5 kJ mol(-1) for CO2-CF3CH2CH3. This value is less than interaction energies typical for hydrogen bonding but greater than the London dispersion values reported for the interaction Of CO2 with the carbonyl group of poly(methyl methacrylate) (PMMA). Electrostatic potential distributions indicate a small redistribution of electron density to the fluorine atoms of the trifluoroalkanes and to the oxygen atoms of CO2 in the CO2-CF3CH3 and CO2-CF3CH2CH3 dimers. Sorption and molecular association Of CO2 with PTFEP has been investigated by molecular simulation of an amorphous cell using the COMPASS molecular mechanics force field. CO2 Sorption isotherms obtained by Grand Canonical Monte Carlo (GCMC) simulation indicate an upward deviation from the linear relationship between log S and the Lennard-Jones potential well depth parameter, epsilon/k, in agreement with reported permeability data. Pair-correlation analysis obtained from molecular dynamics simulation show strong correlation Of CO2 with the trifluoromethyl group of PTFEP in agreement with the MP2 results showing an association Of CO2 with both CH3CF3 and CH3CH2CF3. (C) 2003 Elsevier Science Ltd. All rights reserved.
引用
收藏
页码:4363 / 4372
页数:10
相关论文
共 40 条
  • [1] THE ROLE OF LONG RANGED FORCES IN DETERMINING THE STRUCTURE AND PROPERTIES OF LIQUID WATER
    ANDREA, TA
    SWOPE, WC
    ANDERSEN, HC
    [J]. JOURNAL OF CHEMICAL PHYSICS, 1983, 79 (09) : 4576 - 4584
  • [2] QUADRUPOLE MOMENT OF CARBON DIOXIDE MOLECULE
    BUCKINGHAM, AD
    DISCH, RL
    [J]. PROCEEDINGS OF THE ROYAL SOCIETY OF LONDON SERIES A-MATHEMATICAL AND PHYSICAL SCIENCES, 1963, 273 (1352) : 275 - +
  • [3] SORPTION AND TRANSPORT OF INERT-GASES IN PVF2/PMMA BLENDS
    CHIOU, JS
    PAUL, DR
    [J]. JOURNAL OF APPLIED POLYMER SCIENCE, 1986, 32 (05) : 4793 - 4814
  • [4] Molecular simulation of glassy polystyrene: Size effects on gas solubilities
    Cuthbert, TR
    Wagner, NJ
    Paulaitis, ME
    [J]. MACROMOLECULES, 1997, 30 (10) : 3058 - 3065
  • [5] Molecular dynamics simulation of penetrant diffusion in amorphous polypropylene: Diffusion mechanisms and simulation size effects
    Cuthbert, TR
    Wagner, NJ
    Paulaitis, ME
    Murgia, G
    D'Aguanno, B
    [J]. MACROMOLECULES, 1999, 32 (15) : 5017 - 5028
  • [6] Fluorocarbons dissolved in supercritical carbon dioxide. NMR evidence for specific solute-solvent interactions
    Dardin, A
    DeSimone, JM
    Samulski, ET
    [J]. JOURNAL OF PHYSICAL CHEMISTRY B, 1998, 102 (10): : 1775 - 1780
  • [7] A new method for deriving atomic charges and dipoles for n-alkanes:: investigation of transferability and geometry dependence
    Delhommelle, J
    Granucci, G
    Brenner, V
    Millié, P
    Boutin, A
    Fuchs, AH
    [J]. MOLECULAR PHYSICS, 1999, 97 (10) : 1117 - 1128
  • [8] Dinoia TP, 2000, J POLYM SCI POL PHYS, V38, P2832, DOI 10.1002/1099-0488(20001101)38:21<2832::AID-POLB120>3.0.CO
  • [9] 2-2
  • [10] GAS-TRANSPORT IN POLY(VINYLIDENE FLUORIDE) - EFFECTS OF UNIAXIAL DRAWING AND PROCESSING TEMPERATURE
    ELHIBRI, MJ
    PAUL, DR
    [J]. JOURNAL OF APPLIED POLYMER SCIENCE, 1986, 31 (08) : 2533 - 2560