J. Genzer et al., MEAN-FIELD THEORY OF THE INTERFACE BETWEEN A HOMOPOLYMER AND A BINARY-POLYMER MIXTURE, The Journal of chemical physics, 105(22), 1996, pp. 10134-10144
In this paper we investigate the properties of the interface between a
homopolymer (A) and a binary polymer mixture (B:C). We have extended
the self-consistent field (SCF) model of Helfand [Macromolecules 25, 1
676 (1992)] by including the effects of the numbers of segments of pol
ymers on the polymer volume fractions, the interfacial excess of B, (-
)(similar to B), the interfacial tension, gamma(ABC), the interfacial
width, w(ABC), and the A-B interfacial overlap, w(AB). Other paramete
rs include the polymer interaction parameters, chi(AB), chi(AC), and c
hi(BC), and the B volume fraction in the B:C mixture, phi(B infinity).
As expected, the B component segregates to the A/B:C interface when A
-B interactions are more favorable than the A-C ones (chi(AB)<chi(AC))
This interfacial adsorption lowers the interfacial tension and width
compared to the pure AIC case, demonstrating the compatibilizing effec
t of B. As chi(BC) varies from favorable to unfavorable, a segregation
is found to increase. Similarly, al constant interaction parameters,
B segregation increases as the number of the B segments increases. Fur
thermore, the addition of a small amount of high molecular weight B to
an immiscible AJC blend is found to reduce greatly gamma(ABC) and thu
s stabilize the system, Calculations for the case of an athermal mixtu
re B:C with chi(AB)=chi(AC) reveals that the shorter chains are ''entr
opically driven'' to the A/B:C: interface. (C) 1996 American Institute
of Physics.