Monolayer films on the neutral water substrate were obtained by spreadingN-trifluoroacetic anhydride (NTF)-modified nylon 66 or nylon 612 in chloroform solutions. Alternatively, monolayer films were obtained by spreading from nylon 66 solutions in the 31 mixture of benzene (B) and phenol (P). The temperatures studied are 10.3�, 14.7�C, and 19.4�C. The isothermss of surface pressure (), and surface moment () against surface area per residue (A) were determined. The -A isotherms of the NTF-modified nylon 66/chloroform and the nylon 66/BP were found to be an expanded type, while that of NTF-modified nylon 612/chloroform was of a condensed type. The NTF-modified nylon 66/chloroform solutions could yield well-spread films even higher concentrations than nylon 66/BP solutions. In the -A isotherms at 10.3� and 14.7�C, the surface moments are constant at 143 mD/residue for NTF-modified nylon 66/chloroform, and 340 mD/residue for nylon 66/BP until the surface area reaches where the -A isotherms show a transition point. After the transition point, the surface moments for both systems drop steadily. However, the surface moment at 19.4�C shows a maximum at the transition point. Possible configuration of the nylon 66 residue in monolayer is discussed.
Colloid & Polymer Science ,Volume 273, Number 1, p.16-22