Glass transition in random copolymers

Glass transition of an amphiphilic random copolymer and relation to the Ising model of spin-glass

“…The numerical analysis shows that in the vicinity of transition only correlations on the first mode are essential, F ab 1 , a = b. In the globular state the density of the globule is mainly determined by the balance between two-and three-body terms, and the spring term can be neglected to the first approximation [18]. Therefore, we neglect the spring term κ sin 2 (πq/N ) in the set of saddle point equations,…”

“…( 8) in the limit N 1. This provides us with an opportunity to pursue a numerical study of the complete phase behaviour [18] by solving the set of equations (10) in the limit n → 0.…”

Dynamic Heterogeneity in Random Copolymers of Polymethacrylates Bearing Different Polyhedral Oligomeric Silsesquioxane Moieties (POSS)

“…The situation is different in random copolymers where a single glass temperature is commonly anticipated. Indeed, many random copolymers were investigated with differential scanning calorimetry (DSC), − rheology, − ,,− dielectric spectroscopy (DS), ,,, ellipsometry, , molecular dynamics simulations, and theory. There is now a vast literature on the composition dependence of glass temperature in such systems. As an example, a single study reported a data set comprising more than 400 glass temperatures of several random copolymers with glass temperature difference of pure components, Δ T g , ranging from 1 to 165 K. The composition dependence of the glass temperatures in random copolymers has been discussed in terms of the Gordon and Taylor or the DiMarzio and Gibbs equations that assume respectively volume additivity of the repeat units and additivity of “flexible” bonds, thus emphasizing packing vs intermolecular effects.…”