Mixed films of poly( n-hexyl isocyanate) and poly(vinyl acetate) at the air–water interface

Abstract

We study interfacial properties of rigid-rod-like poly( n-hexyl isocyanate) (PHIC), flexible poly(vinyl acetate) (PVAc), and mixed films of PHIC and PVAc spread at the air–water interface as a function of the molar fraction of PHIC by surface pressure measurements and fluorescence microscopy. From the plots of the experimental mean area of the mixed polymer films at a constant surface pressure as a function of the molar fraction of PHIC in the mixed films, the binary mixtures of PHIC/PVAc were concluded to be compatible at the air–water interface. This means that the hydrophobic hexyl group of PHIC takes a horizontal orientation to the air–water interface rather than a perpendicular one, leading to PHIC and PVAc having the same interfacial orientation. Compatibility of the binary mixtures of PHIC/PVAc at the air–water interface is also confirmed by their fluorescence microscopic images, since PHIC proves to be inhomogeneous and PVAc is homogeneous with the aid of a fluorescence probe, respectively.