Anomalous Transport of Penetrants in Polymeric Membranes

Abstract

The fundamental study of small organic molecule transport in polymers has been actively pursued for more than two decades⁽¹⁾. These investigations have included a wide variety of polymers and penetrants over a broad range of experimental conditions. Many investigators were concerned with a specific transport feature which they implicitly suggested was characteristic of the given polymer-penetrant pair. These classes of behavior include:

• Poiseuille or Pore Flow⁽²⁾

• Concentration Independent Fickian Diffusion⁽³⁾

• Concentration Dependent Fickian Diffusion^(4,5,6,7)

• Time Dependent Diffusion Anomalies^(8,9,10)

• Case II Transport^{(11,12,13,14,15,16)}

• Solvent Crazing-Stress Cracking^{(10,13,14,17,18,19,20)}