Segregation of block copolymers to interfaces between immiscible homopolymers

Abstract

The equilibrium segregation of deuterated polystyrene-poly(2-vinylpyridine) diblock copolymers to interfaces between high molecular weight polystyrene and poly(2-vinylpyridine) homopolymers was measured by forward recoil spectrometry. The dependence of the integrated segregation on the equilibrium copolymer concentration in the PS phase is compared to predictions from a mean-field theory in which the copolymer chemical potential is the relevant parameter. Predictions from the theory are quantitatively accurate for values of the copolymer chemical potential, which are below a certain limiting value associated with the formation of block copolymer micelles. The segregation behavior in the regime where micelles are present is complicated by a strong tendency for micelles to segregate to the free polystyrene surface and by a weaker tendency for micelles to segregate to the interfacial region. Values of the copolymer chemical potential at the micelle transition are obtained from a careful analysis of the data and are in reasonable agreement with predictions from a simplified theory of micelle formation.

Strategies for compatibilization of polymer blends

“…Beyond that concentration, which is usually in the range of a few wt%, a plateau is observed in the ultimate mechanical properties. [164][165][166] SEM micrographs convincingly confirm that the more drastic change in the PS/PE phase morphology occurs when as low as 0.5 wt% of HPB-b-PS is added, and that no further significant modification is observed above 2 wt%. This conclusion also holds when the ultimate mechanical properties are concerned [27] .…”

Static and dynamic properties of the interface between a polymer brush and a melt of identical chains

“…Thereby, it lowers the interfacial tension and, for sufficiently large surface excess, each block forms a polymer brush in contact with the homopolymer-rich bulk phase. 12,13 The interdigitation between brush and homopolymer chains determines many mechanical properties of the interface. 14,15 While the equilibrium properties of these copolymer brushes at the interface between incompatible homopolymers (as well as brushes formed from end-adsorbed chains) resemble those of irreversibly grafted polymer brushes, their dynamic properties might substantially differ due to the in-plane mobility.…”

Monte Carlo simulations of copolymers at homopolymer interfaces: Interfacial structure as a function of the copolymer density

“…The structure of copolymers at interfaces has been studied intensely in experiments [13,16,[26][27][28][29][30][31][32][33][34][35][36], and theoretically by various refined mean field theories [37][38][39][40][41]. Computer simulations provide a useful way of obtaining additional structural information, and testing theoretical concepts [42].…”