Concentration dependence of water dynamics in poly(ethylene oxide)/water solutions from molecular dynamics simulations

被引:47
作者
Borodin, O [1 ]
Bedrov, D [1 ]
Smith, GD [1 ]
机构
[1] Univ Utah, Dept Mat Sci & Engn, Salt Lake City, UT 84112 USA
关键词
D O I
10.1021/jp012949t
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
We have performed molecular dynamics simulations of aqueous solutions of poly(ethylene oxide) (PEO) in order to investigate the influence of the polymer on water dynamics. Simulations were performed on 12 repeat unit CH3-capped PEO chains (530 Da) at 318 K covering a composition range (polymer weight fraction) from 0.17 to 1.0. The simulations employed an ab initio quantum-chemistry-based PEO/water and PEO/PEO force field together with the TIP4P (four-point transferable intermolecular potential) water model. Water translational and rotational diffusion were found to slow monotonically, whereas water-water and water-ether hydrogen bond lifetimes increased with increasing polymer concentration. The slowing of water dynamics in PEO/water solutions was associated with PEO-water interactions that are moderated in concentrated solutions by the formation of water clusters. Water translational motion could be ascribed to a combination of free water (water not involved with PEO hydration) that exhibited bulklike water dynamics and bound (hydrating water) whose motion was strongly correlated with that of the PEO molecule. Water rotational motion was found to be strongly correlated with translation motion and exhibited increasing anisotropy with increasing PEO concentration indicative of preferred rotation of the water molecules around their dipole moment vector. At high PEO concentration, water and ether oxygen atoms exhibited well pronounced subdiffusive behavior occurring on a picosecond time scale that disappears upon dilution. The characteristic length scale for the water subdiffusive behavior associated with water caging correlates well with nearest-neighbor ether oxygen-ether oxygen distance.
引用
收藏
页码:5194 / 5199
页数:6
相关论文
共 38 条
[1]  
ALBERTSSON PA, 1995, AQUEOUS BIPHASIC SEPARATIONS, P21
[2]  
Allen M. P., 1987, COMPUTER SIMULATIONS, DOI [10.1093/oso/9780198803195.001.0001, DOI 10.1093/OSO/9780198803195.001.0001]
[3]   Dynamic properties of aqueous solutions of ethylene glycol oligomers as measured by the pulsed gradient spin-echo NMR technique at 25 degrees C [J].
Ambrosone, L ;
DErrico, G ;
Sartorio, R ;
Costantino, L .
JOURNAL OF THE CHEMICAL SOCIETY-FARADAY TRANSACTIONS, 1997, 93 (22) :3961-3966
[4]  
[Anonymous], POLYM MAT SCI ENG
[5]   INTERACTION BETWEEN PARTICLES SUSPENDED IN SOLUTIONS OF MACROMOLECULES [J].
ASAKURA, S ;
OOSAWA, F .
JOURNAL OF POLYMER SCIENCE, 1958, 33 (126) :183-192
[6]   Molecular dynamics simulations of 1,2-dimethoxyethane/water solutions. 1. Conformational and structural properties [J].
Bedrov, D ;
Borodin, O ;
Smith, GD .
JOURNAL OF PHYSICAL CHEMISTRY B, 1998, 102 (29) :5683-5690
[7]   Simulation and QENS studies of molecular dynamics in aqueous solutions of 1,2-dimethoxyethane [J].
Bedrov, D ;
Borodin, O ;
Smith, GD ;
Trouw, F ;
Mayne, C .
JOURNAL OF PHYSICAL CHEMISTRY B, 2000, 104 (21) :5151-5154
[8]   Molecular dynamics simulation of 1,2-dimethoxyethane/water solutions. 2. Dynamical properties [J].
Bedrov, D ;
Borodin, O ;
Smith, GD .
JOURNAL OF PHYSICAL CHEMISTRY B, 1998, 102 (47) :9565-9570
[9]   Molecular dynamics simulations of 1,2-dimethoxyethane in aqueous solution: Influence of the water potential [J].
Bedrov, D ;
Smith, GD .
JOURNAL OF PHYSICAL CHEMISTRY B, 1999, 103 (18) :3791-3796
[10]   Temperature dependence of water dynamics in poly(ethylene oxide)/water solutions from molecular dynamics simulations and quasielastic neutron scattering experiments [J].
Borodin, O ;
Trouw, F ;
Bedrov, D ;
Smith, GD .
JOURNAL OF PHYSICAL CHEMISTRY B, 2002, 106 (20) :5184-5193