The influence of gelation on the mechanism of phase separation of a biopolymer mixture

The influence of the gelation of one component (gelatin) on the phase separ ation and morphology of an aqueous mixture of gelatin and dextran has been investigated. Small angle light scattering and confocal microscopy experime nts show that the mechanism of phase separation is similar to spinodal deco mposition, even in the presence of a rapid gelation. At temperatures well b elow the gelation temperature the phase separation kinetics are halted by t he gelation, resulting in an immobile, interconnected morphology. This effe ct is seen as a pinning of the peak in the light scattering data. We also s how that the gelation affects the position of the scattering peak, effectiv ely deepening the quench as the gelation proceeds, through an apparent incr ease in molecular weight. (C) 2001 Elsevier Science Ltd. All rights reserve d.