| The surfactants pictured below were synthesized and their surface behavior and polymerization rates in a Langmuir monolayer studied.*; Surface pressure and potential vs. mean molecular area isotherms of the substituted anilines were generated and the results were attributed to the orientation of the aromatic rings at the interface. Alkyl substituted aniline has been shown, in this and previous studies, to polymerize at the air-aqueous interface when a strong chemical oxidant and acid are present in the subphase. The reactivities of the aniline derivatives were studied under different conditions. When the polymerizations of 2- and 3-pentadecylaniline were compared, the rate of reactivity of 2-pentadecylaniline was more dependent on the applied surface pressure than 3-pentadecylaniline. Further, there was a more significant autoacceleration effect present during the 2-pentadecylaniline polymerization. Reaction rates of 2- and 3-(1-octadecynyl)aniline were then compared under the same polymerization conditions. The initial rate constant for 2-(1-octadecynyl)aniline was significantly greater than that of 2-pentadecylaniline, and autoacceleration was not detected. The initial rate constant of 3-(1-octadecynyl)aniline polymerization was similar to that of 3-pentadecylaniline. Reaction rates were explained in terms of electronic and orientational differences in the monomers at the air-aqueous interface.; On a water subphase, methyl 17-(2-aminophenyl)heptadecanoate and 17-(2-aminophenyl)heptadecanoic had multi-phase behavior. The results suggest that at low surface pressures, both polar ends of the molecules were adsorbed to the water surface, but at high surface pressures only one polar group per molecule was adsorbed to the subphase. Surface potential data indicated that, in the case of methyl 17-(2-aminophenyl)heptadecanoate, the anilinium groups were oriented away from the interface, while in the case of 17-(2-aminophenyl)heptadecanoic, ion pairs were formed and a mixture of the head groups was adsorbed to the interface. When these monomers were reacted at low surface pressure ( p = 5mN m-1), only low molecular weight oligomers were produced, which was attributed to the hinderance of the non-reactive polar end.; 1,22-Bis(2-aminophenyl)docosane was polymerized at the air-aqueous interface to produce a unique, 2-dimensional network polymer. The material produced was the characteristic blue of polyaniline and was insoluble in the solvents that usually dissolve polyaniline and poly(pentadecylaniline). Further, the material could be lifted from the Langmuir trough in essentially one piece, indicating mechanical strength not usually observed in materials produced in Langmuir films. The surface and polymerization behavior of this polymer mirrored many of the properties of 2-pentadecylaniline.; *Please refer to dissertation for diagram. |
