INFLUENCE OF PH AND TEMPERATURE ON POLY(ISOBUTYL CYANOACRYLATE) MONOLAYERS

Surface pressure-area (PI-A) isotherms of monolayers of poly(isobutyl cyanoacrylate), a polymer used in the preparation of nanoparticle drug carriers, were recorded on subphases of pH 2, 6 and 10 at temperature s between 10 and 35-degrees-C. The isotherms exhibit a plateau region at a surface pressure that depends on pH (PI(pH 6) < PI(pH 2) << PI(pH 10)) and also decreases slightly with increasing temperature. Since a pplication of the Clausius-Clapeyron equation to the plateau yields sm all positive DELTAH and DELTAS values, this region is interpreted as r eflecting reorientation of the polar groups of the polymer under compr ession; this interpretation appears to be supported by the hysteresis behaviour of the monolayer.