Adsorption of a minority component in polymer blend interfaces

We analyze the adsorption per interfacial thickness of the minority component C, ${\mathrm{\Gamma }}_{\mathit{C}}$, in the interfaces between A and B rich phases in ternary polymer blends as a function of ${\mathit{cph}\mathit{ī}}_{\mathit{C}}$<cphi${\mathrm{¯}}_{\mathit{A}}$=cphi${\mathrm{¯}}_{\mathit{B}}$, where ${\mathit{cph}\mathit{ī}}_{\mathit{I}}$ is the mean composition of I, and the net interaction per thermal energy between I and J, ${\mathrm{\chi }}_{\mathit{I}\mathit{J}}$. We find ${\mathrm{\Gamma }}_{\mathit{C}}$ solving numerically the nonlinear decomposition equations in the steady state. When C is nonselective, ${\mathrm{\chi }}_{\mathit{A}\mathit{C}}$=${\mathrm{\chi }}_{\mathit{B}\mathit{C}}$=η${\mathrm{\chi }}_{\mathit{A}\mathit{B}}$, ${\mathrm{\Gamma }}_{\mathit{C}}$ increases as η increases and it is linear with ${\mathit{cph}\mathit{ī}}_{\mathit{C}}$ for ${\mathit{cph}\mathit{ī}}_{\mathit{C}}$≪cphi${\mathrm{¯}}_{\mathit{A}}$+cphi${\mathrm{¯}}_{\mathit{B}}$. For selective C, ${\mathrm{\chi }}_{\mathit{A}\mathit{C}}$=η${\mathrm{\chi }}_{\mathit{A}\mathit{B}}$ and ${\mathrm{\chi }}_{\mathit{B}\mathit{C}}$=ɛ${\mathrm{\chi }}_{\mathit{A}\mathit{B}}$, in the case of minimum adsorption, η=0, ${\mathrm{\Gamma }}_{\mathit{C}}$ decreases as ɛ increases and it vanishes when ɛ≥1. © 1996 The American Physical Society.