Rukhlya E G, Yarysheva L M, Volynskii A L, Bakeev N F
Faculty of Chemistry, M. V. Lomonosov Moscow State University, Leninskie gory 1, Moscow 119234, Russia.
Phys Chem Chem Phys. 2016 Apr 14;18(14):9396-404. doi: 10.1039/c5cp07842c. Epub 2016 Mar 16.
Solvent crazing involves the development of a highly dispersed fibrillar-porous structure with dimensions of pores and craze fibrils of about 2-20 nm, and crazing by itself can be treated as a universal method for the development of nanoscale porosity. The penetration and release of poly(ethylene oxide) macromolecules into and from the crazes during the development of the nanoporous structure of poly(ethylene terephthalate) have been studied. In particular, PET has been deformed in dilute or semidilute (unentangled as well as entangled) solutions of PEO (a Mw of 4 and 40 kDa) via the mechanism of solvent crazing. Hydrodynamic coil radii Rh, blob sizes ξ, and concentration ranges (crossover and entanglement concentrations) have been determined for the PEO solutions. The evolution of the craze structure (change in porosity W and pore diameters d) has been described as a function of the tensile strain of PET during its drawing in an adsorption-active medium and in the PEO solutions. PEO has been shown to penetrate into the nanoporous structure of the crazes under the conditions corresponding to Rh≤d and ξ < d. It has been shown that coagulation processes in the structure of crazed PET, PEO adsorption at the highly developed surface of PET, and the mechanism of PEO transport in the nanopores are equally important factors affecting the direction of the macromolecule mass transfer in the nanopores (penetration or release) and PEO content variation as a function of PET tensile strain.
溶剂致开裂涉及形成一种高度分散的纤维状多孔结构，其孔隙和银纹纤维的尺寸约为2 - 20纳米，银纹化本身可被视为一种形成纳米级孔隙率的通用方法。研究了在聚对苯二甲酸乙二酯纳米多孔结构形成过程中，聚环氧乙烷大分子进入和离开银纹的渗透和释放情况。具体而言，通过溶剂致开裂机制，使聚对苯二甲酸乙二酯在聚环氧乙烷（分子量分别为4 kDa和40 kDa）的稀溶液或半稀溶液（非缠结以及缠结）中发生形变。已测定了聚环氧乙烷溶液的流体力学线圈半径Rh、链段尺寸ξ以及浓度范围（交联浓度和缠结浓度）。描述了在吸附活性介质和聚环氧乙烷溶液中拉伸聚对苯二甲酸乙二酯时，银纹结构的演变（孔隙率W和孔径d的变化）与聚对苯二甲酸乙二酯拉伸应变的函数关系。结果表明，在Rh≤d和ξ < d的条件下，聚环氧乙烷会渗透到银纹的纳米多孔结构中。研究表明，银纹化聚对苯二甲酸乙二酯结构中的凝聚过程、聚环氧乙烷在聚对苯二甲酸乙二酯高度发达表面的吸附以及聚环氧乙烷在纳米孔中的传输机制，都是影响纳米孔中大分子传质方向（渗透或释放）以及聚环氧乙烷含量随聚对苯二甲酸乙二酯拉伸应变变化的同等重要因素。
