Spreading behavior of short-branched N-alkylacrylamide polymers and the formation of Langmuir-Blodgett films

The spreading behavior of poly(N-alkylacrylamides) with short-branched alkyl substituents (isobutyl (piBA), tert-butyl (ptBA), isopentyl (piPA), tert-pentyl (ptPA), and neopentyl (pNPA)) on the water surface was investigated by measurement of surface pressure (pi)-area (A) isotherms. These isotherms showed that condensed monolayers are formed for all the short-branched alkylacrylamide polymers. Branched alkyl substituents in the alkylacrylamide polymers were found ta be more suitable to formation of a stable monolayer than are straight alkyl substituents with the same chain length that had been investigated in a previous study. The condensed polymer monolayers can be transferred successively onto solid supports by both downward and upward strokes, yielding Y-type uniform polymer LB films. Film thickness was measured by X-ray diffraction measurement. The quality of the polymer LB films deposited onto glassy carbon electrodes was estimated by means of cyclic voltammetry of the redox couple of potassium ferri- and ferrocyanide in aqueous solutions.