UV/vis spectroscopic monitoring of polyelectrolyte adsorption onto monolayers of azobenzene amphiphiles

摘要

The complexation of an azobenzene-containing carboxylic acid amphiphile with a cationic poly(p-phenylene) polyelectrolyte at the air/water interface results in changes of the monolayer structure. Compared to the monolayer of the amphiphile on pure water, a more expanded liquidlike structure can be suggested for the complex monolayer according to the increased area per amphiphilic molecule and Brewster angle microscopy. Furthermore, aggregation of the azobenzene moieties is suppressed in the complex. The differences in the spectral properties of the pure amphiphile monolayer and the polyelectrolyte complex monolayer due to their different structural order can be employed for investigation of the adsorption process: The adsorption of the polyelectrolyte to an already compressed amphiphile monolayer results in structural rearrangements and can, therefore, be monitored in situ as a change in the monolayer UV/vis spectra. References: 29