The permeability of a disazothiophene dye solute in polymer matrices above the glass transition

Abstract The permeability of a functionalized dye solute in various amorphous polymers above the glass transition temperature has been investigated using dye diffusion thermal transfer printing. A disazothiophene dye molecule was transferred from a constant dye-donor polymer matrix to a variety of dye-acceptor polymer matrices. All dye-acceptor polymers were amorphous, but their chemical structures, glass transition temperatures and solubility behaviours were modified. Dye transfer during a constant print cycle time (i.e. a constant temperature profile) was found to depend on both the diffusivity and the solubility of the solute. Using the solution-diffusion model of permeability as a starting point, equations were developed relating solute permeability to structural characteristics of the components. An excellent correlation has been made for solute permeability as a function of polymer T g and dye-polymer affinity as defined by solubility parameter differences.