Viscoelastic (Non‐Fickian) Diffusion

Abstract

This review paper deals with mass transport in macromolecular materials. The study of mass transport through polymeric composite materials for example has applications in a variety of areas such as coatings, packaging and gas separations, to name just a few. Here we discuss several models for diffusion as well as several experimental techniques. In particular, we discuss models for case II diffusion, from a continuum mechanics point of view as well as via a mesoscopic theory. Variables such as temperature, molecular structure and mechanical deformation, affecting mass transport are also discussed.

Water absorption, retention and the swelling characteristics of cassava starch grafted with polyacrylic acid

“…An extension of the Fick's law to compensate for this swelling, was proposed by Crank (Crank, 1975) and followed by other authors (Alfrey, Gurnee, & Lloyd, 1966;Camera-Roda & Sarti, 1990;De Kee, Liu & Hinestroza, 2005;Franson & Peppas, 1983;Frisch, 1980;Fuhrmann, 1979;Puri, Liu, & De Kee, 2008;Rogers, 1985). The mass transport in macromolecular material involves a complex process, which can be influenced among others by the internal structure of the polymer (De Kee et al, 2005;Franson & Peppas, 1983), glass transition temperature (Wikipedia, 2011), effects of swelling and relaxation and the retardation time of the polymer matrix (Puri et al, 2008), the chemical nature of the diffusing molecules (Rogers, 1985) and mechanical deformation (De Kee et al, 2005).…”

“…The mass transport in macromolecular material involves a complex process, which can be influenced among others by the internal structure of the polymer (De Kee et al, 2005;Franson & Peppas, 1983), glass transition temperature (Wikipedia, 2011), effects of swelling and relaxation and the retardation time of the polymer matrix (Puri et al, 2008), the chemical nature of the diffusing molecules (Rogers, 1985) and mechanical deformation (De Kee et al, 2005).…”

Mathematical Modeling of Hydrogels Swelling Based on the Finite Element Method

“…where M t and M ∞ are the cumulative amounts of water at time t and infinite time (equilibrium), respectively, k is a structural/geometric constant for a particular system and n is designated as "release exponent" representing the release mechanism [9].…”

Physicochemical Properties and Field Evaluation of Monolithic Wax Formulations for the Controlled Release of a Forest Pest Pheromone

“…19 For sulcatone, we obtained that in paraffin wax mp 70-80 ºC, paraffin wax mp 53-57 ºC, paraffin oil (60%)/ paraffin wax mp 53-57 ºC (40%), stearin and bees wax matrices, pheromone component transport would occur by non Fickian diffusion. However, in carnauba wax and in lanolin wax matrices, Fickian diffusion would be the responsible transport mechanism.…”