C. Michon et al., CONCENTRATION-DEPENDENCE OF THE PROPERTIES OF GELATIN AND IOTA-CARRAGEENAN SYSTEMS AT THE GEL POINT, Journal de chimie physique et de physico-chimie biologique, 93(5), 1996, pp. 819-827
Iota-carrageenan and gelatin gel properties are studied through the ev
olution of the frequency dependence of the storage and the loss moduli
during gelation or melting near the critical point at several concent
rations. The linear viscoelastic properties at the percolation thresho
ld follow a power law G'(omega) proportional to G '' (omega) proportio
nal to omega(Delta). The critical point is characterized by tan delta
G ''/G' = tan(Delta.pi/2) independently of the frequency and it may be
precisely located using the variation at several frequencies of tan d
elta versus any parameter controlling the advancement of gelation or m
elting (time, temperature or concentration). The effect of concentrati
on has been studied and state diagrams [T = f(C)] are drawn for both b
iopolymers. A detailed study of Delta versus polymer concentration is
carried out: values of Delta in the range 0.72 - 0.36 are obtained and
they are compared to published results and discussed.